Yeah I've been reading lots of bitching that Apples hasn't opened up AAC.
With Tiger coming out next month and Apple going on about the wonders of QuickTime 7 with H.264 maybe something is in the works but that doesn't help at all with what you are doing.
http://www.apple.com/macosx/tiger/quicktime.html
I noticed that ABEN uses RealPlayer for their Mac customers.