Beatles Rock Band DLC restricted to that game only
Harmonix creative director Josh Randall has told 1UP that if you want to play the Beatles song in Beatles: Rock Band, then you're going to have to buy the game as downloadable content for the title won't be compatible with other versions of the game.
However, it works both ways too. If you're a Beatles Rock Band only owner and want to sample other track, you'll simply have to buy another game in order to do so.
The game is out on September 9 '09.