If you browse around here on the homepage or go over to Mortality.net, you can find a bunch of nifty DM helpers in their files section. As for using dry erase markers on plastic sheet protectors, don't! Use non-permanent Sanford pens (hint: they look like the permanent kind but will say "non-permanent" instead) and a damp papertowel instead. Dry erase doesn't work on plastic sheet protectors, at least not on the ones I have. The one time I tried dry erase, I wound up with my markings on there permanently. Overhead projector pens are what you want. Dry erase also makes permanent marks on vinyl, so beware using it on your battlemat!