map-drawing software

[Rebecca]

Does anyone know of software or any other good way to help the artistically challenged make maps of our fictional worlds, for ourselves or for inclusion in the book? My efforts at drawing what I describe are pathetic, to put it mildly, and I would really like a map for my oven reference, at least--I want to be sure my characters are moving around in reasonable ways, and that I don't accidentally plant two important structures on the same spot, etc.