Apple made a reasonable DRM (digital rights management) system for their music store. You can copy to as many iPods you want to buy from them and up to three macs. And more importantly you can burn a cd for your car or old style stereo or your friend. Then you can of course also reimport the cd with a bit of a quality loss.
Despite all that, I am sure it won't take long before someone cracks the system. Any guesses on how long?
Will whoever cracks it be able to make something so protected AACs can just be changed to unprotected or will it be a crack to Quicktime/iTunes or something else?
Will it be before or after iTunes for Windows come out?
Macrumors has a bit more details on AAC.
Oh, and if you haven't tried the new iTunes: The biggest change is that the icon is now green. And it seems like it might support HTTP Range requests for HTTP streams; at least it doesn't disable the playhead slider when playing certain streams. Something to look into