Hey dirty,
I have a whole bunch of these snails as well and kept meaning to search for an ID as well. Your post got me to looking. It seems they are good snails to have. If you can build up an army of them, they seem to be pretty effective algae eaters...
http://reefcentral.com/forums/showth...light=snail+id
http://reefkeeping.com/issues/2004-05/rs/index.htm