That's something that Apple zealots would like to make you think... or even believe themselves... In fact this compression format is much older than Apple's first steps supporting it in QuickTime 6.0, see e.g. the Wiki of Audiocoding.com (new URL): http://www.audiocoding.com/modules/wiki/?page=AAC This is the homepage of the open source AAC encoder FAAC and decoder FAAD2, so reading through their Wiki pages will give you some information about existing implementations in other applications etc: http://www.audiocoding.com/modules/wiki/?page=FAAC http://www.audiocoding.com/modules/wiki/?page=FAAD2 http://www.audiocoding.com/modules/wiki/?page=Software+Audio+Players+for+Windows http://www.audiocoding.com/modules/wiki/?page=MPEG-4+Players http://www.audiocoding.com/modules/wiki/?page=view/Software+Audio+Players+for+Linux/BSD
if you're too lazy to type the commandline for FAAC, try ivan and menno frontend http://www.rarewares.org/