Yahoo! Movies have posted several video clips online from the upcoming musical film Mamma Mia! which stars Julie Walters (Mrs. Weasley).

At the above link you can see Julie performing Take a Chance on Me, Dancing Queen & Chiquitita. There's also a From Stage to Screen feature in which the cast and crew talk about adapting the story for the movie.

Mamma Mia! opens tomorrow in the U.K. and on July 18th in the U.S.