Links 

Google Image Search
 http://www.google.com/imghp?hl=en&tab=wi&q=

FAST Multimedia Search
 http://multimedia.alltheweb.com/

FindSounds.com
 http://www.findsounds.com/

Lycos Multimedia Search
 http://multimedia.lycos.com/

NIX - NASA Image eXchange
 http://nix.nasa.gov/

Exploratorium Digital Assets
 http://hypatia.exploratorium.edu:8080/Cumulus/Standard/Selec
tCatalog2.jsp

Search tools are not just about text any more. There are a number of web sites now available that search for audio, video and picture files.

Google Images has indexed millions of images on the Internet. Odds are you can find an image for just about any topic here.

FindSounds.com is a specialized search engine for finding sound effects on the Web. Search for "frog" and get a nice "ribbit". You can use these sounds in your next school production, or to liven up a slide show.

Lycos provides one of the original sites that allow you to search for a picture, audio, or video. Another site that does a good job is FAST.

For everything Space, try NASA's image exchange site (NIX). It includes everything from rockets to the Orion Nebula.

The Exploratorium in San Francisco is starting to index their extensive collection, including images, educational activities, and other exhibit-related resources! All resources are free for classroom use.