I won't post any spoilers, but the film is about a dog named Bolt (John Travolta) and his human Penny (Miley Cyrus). In additon to the score, there are basically two full songs in the movie. One is actually sung by John and Miley. That comes at the end. The other, by Rilo Kiley's Jenny Lewis, is during a (what I think was a) major scene of the movie. It completely surprised me. I wasn't 100% sure it was her, but the credits confirmed it, and then the credits confirmed that the child actress is also assistant director which had me leaving the movie thinking she had that job, though IMDB points out that she is the voice of a character called "assistant director" (which makes more sense I think).
The Jenny and Miley songs are both on the soundtrack which is otherwise all John Powell's score. Not on the soundtrack: Motorhead's "Dog Face Boy" which has a quick cameo in the movie (no spoilers). The Jenny Lewis (new) and Motorhead (old) songs, and another video that ties them together nicely, below...
Jenny Lewis - Barking At The Moon
Ozzy Osbourne - Bark At The Moon
Motorhead - 1995 - Sacrifice - Dog-Face Boy