Google
http://www.google.com

Yahoo
http://www.yahoo.com

Ask Jeeves
http://www.askjeeves.com

AllTheWeb.com
http://www.alltheweb.com

AOL Search
http://aolsearch.aol.com (internal)
http://search.aol.com/(external)

HotBot
http://www.hotbot.com

MSN Search
http://search.msn.com

Teoma
http://www.teoma.com

AltaVista
http://www.altavista.com

Gigablast
http://www.gigablast.com

LookSmart
http://www.looksmart.com

Lycos
http://www.lycos.com

Open Directory
http://dmoz.org/
　
Netscape Search
http://search.netscape.com