I bled the brakes by myself on the weekend, there is no need to pull the caliper off. Heres how I do it.
Place clear tubing over the nipple, and run it down into a colecting container that has a bit of fluid in the bottom. This stops air bubbles running back up the clear pipe and confusing you when you start bleeding. Then with the top of the resevoir off, make sure there is heaps of fluid in there and then start like this...
Open nipple
Pull brake lever all the way in
Close nipple
Let brake lever out
You will need to do this over and over until when you are pulling the brake lever in there is only fluid flowing out the plastic pipe, and no air bubbles whatsoever. It is vital you make sure the resevoir stays full, or it will just suck in more air To test you brakes leave the nipple shut and pull on the lever, it should be hard as a rock without any sponginess to it whatsoever.
Whilst you are at it, go down the hardware store and buy some 4mm alan head bolts to replace the piece of crap screws that are used to hold on the top of the resevoir. These things always tend to foul up and then you strip the head trying to pull them out. Will save you grief in the future I promise you.