Partners In Rhyme is one of the leading online distributors of royalty free music and sound effects. They distribute their catalogs and the catalogs of hundreds of contributors world wide through three main websites:

Partners In Rhyme
Collections of royalty free music and sound effects available as immediate download and shipped on CD/DVD. They also have a huge archive of free sound effects, midi files, audio software and audio tutorials.

Sound-Effect.com
Search for, preview and download from a library of over 20,000 royalty free sound effects to use in your commercial projects.

Musicloops.com A royalty free music site with over 4000 tracks from some of the best composers on the internet. Easy to search, preview and download.

http://twitter.com/partnersinrhyme for More Free Sound Effects and Royalty Free Music Clips