Theme Music 
At this site, you can download over 100 free theme tunes from dozens of vintage and new TV programs, from both the U.S. and the U.K. Sounds files here are available in several formats, including MP3, AU and WAV files.

Sound Explorer 
Are you trying to locate a particular WAV file quickly? This speedy dictionary-style search engine is the place to go; it indexes over half a million WAV files. Sound Explorer will show you all of the different versions of WAV files and can quickly locate rare songs.

Wavhounds 
An excellent resource for finding sound files, Wavhounds.com queries eight major search engines simultaneously. It's a handy way to find WAV files, as well as other types of sound files, including MIDIs, MP3s, etc.

A1 Free Sound Effects 
This fun resource serves up over 700 free WAV sound effects that include everything from breaking glass to creaking doors to sirens to crackling thunder. The site also accepts requests, if there's a particular sound effect you're looking for.

Prank Calls Unlimited 
This site offers a collection of free, prank phone calls. You'll also find a wild collection of free sound effects and other gags.