Google -- the most popular search engine available.

http://www.google.com/

Ask -- another simple search interface, similar to Google.

http://www.ask.com/

Clusty -- a metasearch engine that groups together your results by similar subjects, or clusters.

http://clusty.com

The Internet Public Library -- Resources for all ages and all needs.

http://www.ipl.org/

Kart00 -- a metasearch engine that displays your results and their relationships visually. Flash player is required.

http://www.kartoo.com

Librarian's Index to the Internet -- provides only selective results to your search, so you don't have to wade through irrelevant sites.

http://lii.org/