The method Karl describes is how I do it. I use the forward trap line to get the job started and then catch the shroud as the boat is coming over. A couple of things to watch out for as you are hoisting the sail this way... Make sure your high side spin sheet doesn't get caught on a sail batten. It helps to have someone at the base of the mast to make sure the sail feeds into the slot smoothly. The only thing to watch out for when lowering the sail this way is to make sure the downhaul is off before you try to unhook, and make sure you lower the sail somewhat after unhooking so it doesn't re-hook as you are bring the boat back upright.

Hull crashing as the boat comes back upright doesn't seem to be much of an issue for me. As the boat is going up, I put one foot on the boat, with one hand on the shroud, and hang off the boat like an X; this way the boat eases back upright. I have a bigger problem with the boat spinning as it's going up and no longer heading into the wind. There is also the fact that it is embarrassing.

If you have someone to help you, put him/her on the other side of the boat to lift the hull (to put the boat on its side,) and catch the hull and lower it (to bring it back upright again.)