Volvo Repair: Brakes, 17 inch wheels, volvo s80

Question
2002 Volvo S80 2.9 non-turbo with 57K miles, 17 inch wheels. I'm told the rotors are below spec and have to be replaced. The dealer put pads on the front at about 50K miles. I know you can't gauge our driving habits but is it normal for the rotors to wear out by 57K miles?
In addition, I am a decent driveway mechanic with lots of tools. Is this a job I can do myself?
One more thing, I was looking for OEM parts on the Internet, and got some good prices, but could not find OEM parts for the rear, only the front (Brembo brand). How can I find OEM parts for the rear? What brands are the OEM parts?
Thanks for your help.

Answer
you did not ask for instructions on how to change them you just asked if it was a job you could do yourself. as you stated "I am a decent driveway mechanic with lots of tools".
I could have offered tips on how to replace them if you had asked.If you are going to do some of your own repairs on your vehicle I would recommend buying a repair manual this will help you with most minor repairs and some not so minor.it will be a great help and usually will have pictures to help illustrate things that would be difficult to explain.