how to replace bathtub faucet?

This faucet is mounted in the wall, a brass faucet body with soldered copper tubing. I know I will have to cut the drywall behind the faucet to get at it (this is in a closet). But how does one get the old faucet body out and install a new one? Should you cut the copper tubing and then sweat the pieces out? Are there fittings to simplify the installation of the new one?