Ogg

A non-proprietary, patent free open source audio compression format that is similar to MP3.

Ogg Vorbis is a completely open, patent-free, professional audio encoding and streaming technology with all the benefits of Open Source.

• http://www.vorbis.com/

• http://www.xiph.org/

• Xiph Wiki

Related: Icecast, Zinf

Also see Theora, Free Video Compression from Xiph