Here's a collection of Free Public Domain Music
Copyrights of music expires but almost no recordings is in the public domain. The aim of the following sites is to provide a recording that have no copyrights so that the public may listen, re-use, or in any way enjoy if for free.
1. MusOpen – This online music library offers free public domain classical music. You can download classical instrumental and vocal music in mp3 format. It supports classical music, composers, history, and background sounds for multimedia works.
2. PublicDomain4U – This is a collection of vintage songs and recordings. It consist of blues, jazz, folk songs, and songs during World War I. It also have a list of free music with musician's or artist's permission for public use.
3. Sound Jay – The music here is free of charge and royalty free but you are not allowed to post the sounds on any web site and make available for download for free or for sale. This is an excellent choice of sound effects that you can use for background sound effects or music tracks for most of your production.
4. Soungle – This site looks like a search engine for public domain sounds. You can search sound effects and musical instruments samples and download it for free.
Here's my list of free to download music, hope you can add more resource that offers public domain music for sound effects and classical music to my site by giving your comments or links below.