MPE Secure Media
Secure streaming media format giving authors, songwriters and publishers complete control over products distributed through the internet.
http://www.destinympe.com/

Study on Audio Compression
Detailed comparison of various audio compression algorithms including ASF, RealAudio, MP3, Ogg Vorbis, MOV, and VQF.
http://ekei.com/audio/

Vianix Corporation
Developed MASC technology (Managed Audio Sound Compression) memory-efficient audio compression algorithm providing voice emulation.
http://www.vianix.com/

The Void: PC Audio Resource
Information about computer audio formats and sound cards.
http://www.voidaudio.net/

AC3Filter
DirectShow AC3 filter.
http://ac3filter.sourceforge.net/

Musepack
Open audio compression format also known as MPC or MPEGPlus/MP+. Based on MPEG1 Layer-2/MP2 algorithms.
http://www.musepack.net/

OptimFROG
Loseless audio compression supporting IEEE Float audio data.
http://losslessaudiocompression.com/

Speex
Open audio codec designed for speech, part of the Xiph.org Foundation.
http://www.speex.org/

True Audio
Open lossless audio codec developed with the main requirements of reasonable compression level and high operation speed.
http://www.true-audio.com/

WavPack
Open audio codec facilitating both loseless compression and a unique hybrid compression mode.
http://www.wavpack.com/

ATRAC: Adaptive Transform Acoustic Coding for MiniDisc
ATRAC is an audio format based on psychoacoustic principles originally used for Sony MiniDisc players.
http://www.minidisc.org/aes_atrac.html

GSM 06.10 Lossy Speech Compression Format
Details about the format and example source code.
http://kbs.cs.tu-berlin.de/~jutta/toast.html

Lossless compression vs. speed
Comparisons of most popular lossless audio formats.
http://web.inter.nl.net/users/hvdh/lossless/main.htm

Rob Nowiks Audio Resource
Site contains discussion of audio formats, related audio algorithms and general audio production techniques.
http://rnowik.com