10Cities.com
Search for the top ten hotels, museums, galleries, etc. in cities around the world. The site only covers London, Paris and Oslo at present, but a big selection is promised soon. Definitely one to watch out for.
http://www.10cities.com/

Answers.com
Features profiles of cities which contain links to external web resources such as weather, map and tourist office sites. If all you want is a quick overview of a city, then click on Answers.com first.
http://www.answers.com/library/City%20Maps

AreaGuides.net
Browse over 39,000 city guides worldwide.
http://www.areaguides.net/

Arrival Guides
Comprehensive and regularly updated travel guides to over 250 destinations worldwide, which you can download for free in PDF format.
http://www.arrivalguides.com/
http://www.fastcheck.se/

Boomtrek
A mobile proximity-based search engine aimed at business travelers, backpackers, travel agents and hotel concierges.
http://www.boomtrek.com/
http://www.boomtrek.net/

Boulevards
Covers topics such as hotels, dining, attractions, real estate and nightlife for destinations in the US and worldwide.
http://www.boulevards.com/

British Airways
This guide covers cities all over the globe and includes information on the local cost of living, vital statistics, culture and attractions.
http://www.britishairways.com/travel/miniguides/

Cities.com
Search a database of 4,332 city guides in 150 different countries. Highly recommended.
http://www.cities.com/

CNN Business Traveller
Information about the eponymous television programme, useful links and an excellent city guide section.
http://www.whatsontheplanet.com/wow/ptnr/cnn/

CNN.com
City guides, travel advice, and up-to-date travel news and articles from CNN.
http://edition.cnn.com/TRAVEL/
http://www.cnn.com/TRAVEL/
http://www.whatsontheplanet.com/wow/ptnr/cnn/

Concierge.com - Destination Guides
Comprehensive travel guide to major cities all over the world.
http://www.concierge.com/worldindex/

Concierge.com - Insider's Guides
Insider guides to some of the most popular cities in the world.
http://www.concierge.com/insiderguides/

Dorling Kindersley
Download a free audio tour guide to Amsterdam, London, Miami, New York, Orlando, Paris, Prague and Rome, courtesy of DK.
http://traveldk.com/about/podcasts

Dorling Kindersley Travel
Glossy online travel guides to destinations worldwide, which you can customize to create your own-tailor-made downloadable/shareable guide.
http://www.travel.dk.com/

Economist.com
City guides to the top business destinations around the world, with content that is genuinely tailored to the needs of the executive traveller. Impressive.
http://www.economist.com/cities/

Epic Trip
Contains short video guides to countries and cities all over the globe, as well as similar guides to hotels in each destination.
http://www.epictrip.com/

Explore.com
Get the lowdown on accommodation, transport, business, sightseeing, entertainment, and much more in dozens of cities worldwide.
http://www.explore-amsterdam.com/

Footprint Travel Guides
The online version of the information-packed destination guides.
http://www.footprintguides.com/

Gridskipper
Entertaining urban travel blog.
http://www.gridskipper.com/

Hg2
City guides for hedonists that come in both book and virtual format.
http://www.hg2.com/
http://www.ahedonistsguideto.com/

Hip Guide
North American and European city guides for the trendy crowd.
http://www.hipguide.com/

Holiday Which?
Excellent downloadable mini-guides to countries, regions and cities worldwide, put together by one of the UK's foremost consumer organizations. In PDF format.
http://www.which.co.uk/holidaywhich/miniguides.html

i-Escape
A hotel booking site that hosts informative city guides as a sideline.
http://www.i-escape.com/

It Is Traveler
Budget and student travel guide with a wealth of information about popular destinations worldwide, including language, climate, cost of living, border crossing and visa formalities, shopping, festivals, food, health and local customs.
http://www.itisnet.com/

Jewish Community
A directory of resources to cities around the world with a substantial Jewish population.
http://www.jewish.com/search/Jewish_City_Guides/

Lorkin.com
The city guides themselves are nothing to shout about, but the accompanying photos and maps most certainly are.
http://lorkers.members.beeb.net/index.htm

nPorta
International city guide that includes a useful events section for each destination.
http://www.nporta.com/cityguides/

OAG
Practical city guides.
http://www.oag.com/oag/website/com/OAG+Connecting+Places/
Home/Connecting+Places+Home

Planetware.com
A searchable database of tourist attractions in every major country in the world. The site boasts thousands of pictures, maps, detailed descriptions and addresses.
http://www.planetware.com/

PodCityGuides
Download over 300 city guides to your iPod absolutely free.
http://www.podcityguides.com/
http://ipod.wcities.com/

SAS City Guides
A configurable city guide from Scandinavian Airlines that allows you to create a customized guide by specifying topics you want information on for a particular destination. The site also includes a wealth of assorted travel tips contributed by SAS cabin crew.
http://www.sasguides.com/

Schmap
Download free dynamic travel guides to cities all over North America and Europe. Each guide contains maps, useful links, suggested tours and top picks, as well as pictures and reviews of major sights, attractions, hotels, restaurants, bars and entertainment venues.
http://www.schmap.com/

Skyteam
The site offers two sets of city guides, one for tourists and another for business travellers.
http://www.skyteam.com/EN/travelResources/

Telepgraph
Each week this leading British newspaper offers a city guide in PDF format that travellers can download from its website and take with them.
http://www.telegraph.co.uk/travel/

The Independent
Podcasts and 48 hour city guides to metros all over the globe.
http://travel.independent.co.uk/

Time Out
Aberdeen to Zurich: eating and drinking, nightlife, accommodation, local attractions, essential contacts.
http://www.timeout.com/

Tiscali.co.uk
A bit of a hit and miss affair - Beijing's restaurant section didn't have anything listed when we visited - but the guide covers all the basics.
http://www.tiscali.co.uk/travel/eworldguides/

TNT Magazine.com
Download free travel guides to topics as diverse as diving and travel gear, as well as destination guides to a host of major tourist spots, at this magazine's website.
http://www.activemag.co.uk/tntguides/
http://www.tntmagazine.com/travelzone/

Toffsworld
City guides to selected destinations worldwide aimed at the well heeled.
http://cityguides.toffsworld.com/

Travel Ape
Insider tips, editor’s picks and information about attractions, hotels, nightlife and more.
http://www.travelape.com/tape/destinations.html

Travel Insider
Features sightseeing itineraries for major tourist destinations worldwide. Each itinerary is stored in Microsoft Word format and can be downloaded for free.
http://www.travelinsider.co.uk/My_Homepage_Files/Page40.html

Travelcreek
One page guides to selected cities and countries worldwide.
http://www.travelcreek.com/

Travelsavers.com
In-depth travel guides from the Travelsavers Travel Club of America.
http://www.travelsavers.com/vacation_planner/city_select.asp

Tripbase
Can't decide where to go? Click on this site, assign a personal weighting to five key vacation preferences (attractions, dining, nature, nightlife and shopping), and it will suggest suitable destinations in response.
http://www.tripbase.com/

Twinroom.com
A concise city guide courtesy of a hotel booking site, which includes information on the best areas to stay in for each city.
http://www.twinroom.com/city_guides/

Utell
Details of cities worldwide including a city overview, important information before you go, sightseeing highlights, arrival information, as well as shopping, culture and nightlife.
http://www.utell.travel-guides.com/world.asp

VGP.com
Download free guides to New York, Boston, Washington DC and Moscow to your PC.
http://www.vgp.com/pdf/pdf_intro.html

Virgin Atlantic
Destination guides in the form of a series of downloadable podcast broadcasts. Only New York was covered when we visited, but it can only be a matter of time before more are added.
http://virginatlantic.loudish.com/

Wcities
A succinct, neatly designed and easy-to-follow city guide that is aimed as much at business travellers as tourists.
http://newton.wcities.com/demo/index.html

Which?
Concise, but informative, city guides taken from the travel magazine published by the British Consumers Association. The guides are in PDF format and can be downloaded for free.
http://www.which.net/holidaywhich/miniguides.html

Wiki Tavel
Offers over 2,300 destination guides and articles written and edited by travellers from around the globe.
http://wikitravel.org/

World 66
An open source travel portal that invites travellers to rate and review everything from hotels to tourist sites in several hundred cities and travel destinations worldwide. This is supplemented by information compiled by local editors. A terrific site.
http://www.world66.com/

World Guides
Presents detailed city guides to many of the world's top cities that feature local information, tourist attractions, museums, art galleries, restaurants, weather information, travel and transport tips, business tips and airport information.
http://www.world-guides.com/

World Travel Net
Information in a limited number of essential categories on cities worldwide, along with the usual selection of travel news, tips and tools.
http://www.world-travel-net.com/

World Travels
Country and city profiles that contain essential information and reviews posted by real travellers.
http://www.wordtravels.com/

World Web.com
Hosts pictures of Australia, Canada, France, Ireland, the UK and US.
http://www.worldweb.com/Photos/

Worldroom.com
Pick a city and then click on the Fast Facts section for details on everything from using the local airport to tipping etiquette.
http://www.worldroom.com/pages/cityguides.phtml

Yahoo! Travel Guides
Well researched and informative city guides to a comprehensive selection of tourist destinations worldwide. The site also features plenty of hotels, restaurants and holidays that have been rated by customers.
http://uk.holidaysguide.yahoo.com/