Audio file types

Adobe Audition CS6 products home page
Adobe Audition help page
AllMusic.Com - good place to download hooks from pop songs
Apple's free GarageBand '11
Apple's free QuickTime 7 Player for Mac or PC
Audacity 2.0.3 - free download
Dick Orkin's Radio Ranch
SoundJay - Free Sound Effects Archive
How Stuff Works - How CDs Work
How Stuff Works - How Hard Drives Work
Media College: free resources for film & digital media production
Stonewashed.net - carefully selected links to free sound effects
FindSounds - has apps for mobile device downloading
Soungle - free sound effects
SoundBible - some are public domain, some require attribution
SoundBoard - more than 488,000 SFX but requires password registration

Websites with audio:
American Rhetoric's Top 100 Speeches site
Colonial Williamsburg audio archive
eNature.com - Birds & Birding
ESPN Radio
History Channel's Famous Speeches and Audio
FreeMusicArchive.org - a library of high-quality, legal audio downloads
Internet Archive's collection of 200,000 recordings in many categories
iStockphoto - has a section for downloading audio but it has audio watermarks
Loudlit.org - literature for your eyes and ears
Major League Baseball Gameday Audio (requires a subscription)
Merriam Webster audio dictionary
National Public Radio podcasts
National Weather Service live streaming audio
New Hampshire police & fire dispatch calls
Soundboard.com
U.S. Supreme Court - argument audio
Virtual Cantor - audio files for people interested in Judaism

White House podcasts