Okay, got me interested I guess.
The trailer doesn't make it look that great though.
One guy on the youtube comments said pretty much what I'm thinking:
"this doesn't even look remotely interesting, but it got a 97% rating on Rottentomatoes from critics, and 93% from rottentomatoes user"
Guest-reviewer on Ebert and Roeper says that the Writer/director describes it as a "video album" calling it almost a musical.
But Roeper says it's TRULY a musical because they are playing the songs in their entirety through the regular course of the film in real-world setting so if they are on a bus then somebody is giving them a dirty look for singing, etc.
"If you're sort of adverse to the broadway translations to film like in DreamGirls or Chicago you get none of that kind of baggage."
trailer:
http://youtube.com/watch?v=utl7TgsUOH4
Ebert and Roeper review:
http://www.youtube.com/watch?v=PvRNNehMJGs&NR=1