Addresses.com
Search for people, addresses or businesses all over the US.
http://www.addresses.com/

Any Who
Online people and business search facility.
http://www.tollfree.att.net/

Bigfoot
One of the best known people finders on the net, and deservedly so.
http://www.bigfoot.com

Free Email Address Directory
Information on finding email addresses, and a whole lot more.
http://www.emailaddresses.com/

Infobel
Directory of telephone, people and business search sites to countries worldwide.
http://www.infobel.com/world/

Internet Address Finder
Over 6.7 million listings, and counting.
http://www.iaf.net/

Lycos
Search for people all over North America by querying public records and the White Pages.
http://peoplesearch.lycos.com/

Switchboard
People, business, telephone and zip code finder.
http://www.switchboard.com/

The Ultimates
Email directory, telephone directories and more.
http://www.theultimates.com/

UK Online
British phone and address finder, and an international email address finder.
http://www.infospace.com/uk.ukol/index_ppl_uk.htm

US Search.com
Search for people, run background checks, search criminal or civil court records, stop identity theft, etc.
http://www.ussearch.com/

WhoWhere?
Yellow page search, public records search, web search, ancestry search.
http://www.whowhere.lycos.com/

World Email Directory
World email directory and address and telephone search facility.
http://www.worldemail.com/

Yahoo!
Email and telephone search facility.
http://people.yahoo.com/