done mine a couple of weeks ago. its a simple job apart from reseting the piston. like james said, you need a caliper reset tool, i got one for £15.
normal calipers you can just push back in but the rear pistons have to be turned at the same time its compressed.
didn't know this when i did mine, had to get a friend to help me reset them by me using a clamp to push in the piston and at the same time my friend turning the piston clockwise with pliers. if you want to do it this way, make sure you don't put the pliers over the rubber part.
hope this helps