For many years now, The Beatles have been arguably the highest profile holdouts from iTunes. Their (technically their rights holders) have shown through agreements like the one with Rock Band, that they are willing to bring the Beatles song catalog into the digital realm.
Couple that with the fact that we've been hearing for some time that Apple is working on a new, more immersive format for iTunes albums, moving beyond simple liner notes. Also keep in mind that the Beatles catalog is in the process of being remastered for a September 9 release, the same date as the next Apple event.
Coincidence? We doubt it.
Apple's "Cocktail" project is rumored to bring together music, behind the scenes video, and interactive liner content. Would there be any better way to pry money from the hands of Beatles fans who already own every piece of Beatles music than with extras that have never been available before. It will also allow Apple to get a huge amount of publicity for the new format.