555-1212 The site allows you to search for telephone numbers for both individuals and businesses in a variety of ways, including through reverse lookups. It also offers fee-based public records searches.
Ancestry.com This site provides free searches for some of its databases including social security death index, phone and address listings and family name message boards. Other more detailed searches are available for a fee.
BigFoot The site provides free searches for telephone numbers and allows you to join for free but more detailed searches have a fee.
InfoSpace InfoSpace Maps, directions, phone numbers, weather and more are available here.
Switchboard This site also has free searches for phone numbers. It is like the site above and does not specialize in "people searches".
WhoWhere The site says it is the way to find people on the Web. WhoWhere allows free searches for phone numbers and Web-wide searches for individuals.
YAHOO People The site provides free searches for phone numbers and email addresses. It has a link to USSearch.com, which offers more detailed searches for a fee.