Area Guides.net
An introduction to the geography and layout of the Italian capital.
http://romeit.ags.myareaguide.com/detail.html?cityguide=gen_intro

Frommer's
Familiarize yourself with the city's layout and neighbourhoods.
http://www.frommers.com/destinations/rome/0064030022.html

Italy Cyberguide.com
Suburban map of the city.
http://www.italycyberguide.com/Geography/cities/rome2000/map-ns.htm

Roman Homes
Glossy pictures and basic information about Rome's main quarters of interest to visitors.
http://www.romanhomes.com/rome-guide-quarters.htm

The 22 Rioni
An historical guide to Rome's 22 central districts.
http://www.geocities.com/mp_pollett/rioni.htm

Yahoo!
Offers a good overview of Rome and its most important areas.
http://travel.yahoo.com/p-travelguide-2524645-rome_introduction-i;_ylt=Aofz1lz.MjI8fpxDZjCV0R7JFWoL