Christian rock doesn't count brah... it's not real music.I think Barlow Girls are great examples ( a group of Christian rock band I think )
The problem with girl bands that too get anywhere they end up pigeon holed into doing shit like Avril Lavigne when they really wish they were doing shit like My Ruin. It's not their fault but it is the record buying public's fault as the old adage goes; you vote with your wallets.
Although why has no one brought up the Yeastie Girls yet?
http://www.youtube.com/watch?v=BoyUUu1rPhE
(Ok so this is the remix by Consolidated but the original really is just a plain song with no music).