|MPEG Audio links :|
Best sound quality in compressed audio: interesting page concerning professional AAC and how it compares to other encoding schemes.
Fraunhofer: Fraunhofer Institute's audio section. Basic technical documentation.
ID3v2: The official website of the new MP3 tagging specification. It provides both the formal and informal specification documents of ID3V2.
Mp3.com: Daily updated mp3 news and free music download.
Mpeg.org: Very complete directory of links to mpeg resources on the net.
VQF.com: Site about the VQF file format.
The Definitive MP3 Benchmark: Good site benchmarking MP3 players and encoders. There are few technical explanations too.