Don't you already have a related thread on your pool?
The tough part about this is getting rid of the concrete. It often makes more sense just to pay to have it removed just because they have to get rid of the waste.
You want to make sure you don't damage the electrical, suction and return lines. They are never where they are supposed to be. You also want to protect the top of the walls and the pool floor.
You don't have to drain the pool, the sides should be held up by supports burried in concrete at the base of the walls. If your pool was built correctly and the walls are not rusted out then you should be able to leve it without decking for a while. That said, generally you want deck to surround a vinal liner pool so the soil next to the pol does not expand and deform the walls.
Finally, when you replace the deck you want to be sure the pool and deck are properly bonded.