The Incompetech blog hosts royalty-free music for a wide variety of movie themes. Though everything on the site is free, donations are accepted.
Cost: Free
Flash Kit is a large archive for royalty-free audio loops that can be used in any Flash project. The site also allows you to submit your own loops and offers Flash tutorials as well.
Cost: Free
This huge database of public domain and free-with-artist-permission music includes its own last.fm radio station, so you can listen to their selection while you surf the Web.
Cost: Free
Musopen is a non-profit focused on improving access and exposure to music. It offers classical music files and the sheet music, available for free download. The database is searchable by composer, instrument, period and form.
Cost: Free
Soundsnap hosts content from the creators of Batman Begins, Million Dollar Baby, Ali, Happy Feet, Star Trek, The Addams Family, Tron, The Hunt for Red October and more. Free to browse and preview.
Cost: Membership packages start at 5 sounds for $9, up to an annual fee of $249 for unlimited sounds.
From ferrets to Monty Python, you can search this enormous selection of over two million sound clips and effects in multiple file types and channels - all for free.
Cost: Free
Type any keyword into the search box to find a range of free, downloadable sound effects for use in audio and video projects.
Cost: Free
Sound Jay contains a collection of free-of-charge and royalty-free sound effects - for personal use only, not further distribution.
Cost: Free
You can find bands and full-length songs here to use in producing slideshows or video. All songs are available in streaming audio and most of the songs are also available as free legal MP3 downloads.
Cost: Free
Jamendo is a huge platform for free and legal music downloads. Available in seven languages, it offers the largest catalog of music under Creative Commons licenses.