What do you use for Maps as a DM of PbP game?

I've recently discovered ditzie, which has a bit of a learning curve (not much, but expect to spend about an hour figuring out how to make maps and tokens in a workable form), but is incredibly simple to use for players. It only has one disadvantage of which I am aware. Whenever a player makes a move, they have to remember to save it (a simple process of pressing Enter) and post the link to the new map, as every time a map is saved, it changes the URL. Aside from that it is an incredible piece of web software for gaming.

I really like ditzie as well. I'll be using it next game.