Searching for this film resulted in no hits here, although I have a sneaking suspicion I may have screwed up the search.
The movie is "Once." It's an Irish film that was recognized at Sundance last year. It's a musical, primarily because the characters are musicians and their music forms part of the story.
In making the film, the directors found the actual musicians who would record the film soundtrack first, intending to look for the actors later. Instead, they decided to use the musicians themselves (Glen Hansard and Marketa Irglova) in the film.
There are a few scenes I would have cut (why does every recording studio soundman have to sit up as though to say, "Golly, these darn kids just might have something!") The camera work is distracting in spots, at least for me. But I would actually consider buying the soundtrack - something I haven't done since, oh, maybe "Miss Saigon." Although with iTunes I'm more likely just to buy the 3 or 4 songs I really liked.
They make up for all their errors by ending the story before they can screw it up.
I recommend this movie to a) anyone who is into singer-songwriters, b) anyone who has thought of him/herself as a musician, c) anyone who has ever loved a musician. Yes, it's a love story, but it's mostly about the love of music.
