Apologetix

I got a CD of these guys for Christmas - it's awesome!

They're a Christian parody band that takes popular, secular music and changes the lyrics to Christian ones. They're also pretty funny. They do everything from classic rock, metal, rap and country. Click the post title for their website.

You can also find some of their stuff by searching for it on YouTube.
Here are a few examples of songs they've made:

I Love Apostle Paul (instead of I Love Rock n Roll)
Welcome to the Judges (instead of Welcome to the Jungle)
Back Intact (instead of Back in Black)
Pray Now (instead of Allstar)
Monkey Scheme (instead of the Monkees theme song)
Jail Got Rocked (instead of Jailhouse Rock)
Kick in the Wall (instead of Another Brick in the Wall)
Meshach (instead of Love Shack)
Bad Dude Risin' (instead of Bad Moon Risin')
The Real Sin Savior (instead of The Real Slim Shady)

They've got tons of CD's. Check them out when you get a chance.