Well, naturally I forgot my camera this morning but I did give these guys a much better look. I don't think they are a harmful snail. They were all over the glass eating algae. There are lots of Zoo's in the tank and I looked very closly and did not see any on them or any of the other corals. I looked again on line at the Collonista sp. and I believe this is what they are.
Scott, this tank has the one's you discribed too, as do my systems at the shop. I've allways refered to them as limpits althought that might be a catch all name for several specices that are similar.
Anyway, thanks everyone. I think I got the answer I needed. I'm going to leave them alone.