Real Networks has release Realplayer 10 the first major free player that can play AAC, Quicktime, Real, Windows Media, MPEG-4, MP3 and many others.
Read Rob Glase chief executive of Real Networks interview with BBC Online
http://news.bbc.co.uk/1/hi/business/3608295.stm
It is still unfortunate that the Mac version is still at Version 9, but lets hope Real Player 10 is coming soon.