LabChirp, Musagi and Sfxr are nice programs to create original music and sound effects for your games.
Visit Bfxr Official Site (make sound fx directly in your browser)
The Zip includes LabChirp, Sfxr and Musagi, please download the programs on the official sites, our mirror are only to preserve files.
Music and Sound FX tools
4.1 MiB - 508 downloads
And if you know some good free program (there are a lot out there) to make music or sound effects put a link in the comments. Thanks and have fun.