*.OGG
.OGG is a container format (OGG file format) for audio or audio and video.
The audio compression component is usually Vorbis, which is somewhat akin to MP3, except it is a open-source, open-standard format. The advantage over WAV is smaller file sizes, but with a minimal loss in quality (depending on what quality settings are used). Vorbis uses a quality parameter from -1 to 10, 5 being the default (about 160kbps). Lower numbers are lower quality. Despite what some people may think, 10 is not lossless, use FLAC for this. Bruce89 13:09, 9 September 2007 (CDT)
The video compression component is Theora, again being a open-source, open-standard format.
Audacity and Goldwave are two popular programs that allow .WAV files to be converted to OGG Vorbis files.