Yahoo People Search - Phone, address, email.

Switchboard - Find a person, business, search by phone number.

WhoWhere? on Lycos - White pages for people; yellow pages for businesses.

AnyWho from AT&T - Yellow Pages, White Pages, Toll-Free Numbers, Maps and Directions

SuperPages from Verizon - Yellow Pages, White Pages, Reverse Phone Book, Map Directions, People Finder, Phone Numbers Search.

Bigfoot - Marketing Lists, Catalogue Purchases, Magazine Subscriptions, Change of Address Records, Real Property Records, Court Records, Business Records, and other public records and publicly-available sources.