Dice rolling has been added to the forums. It seems to work pretty well but it isn't totally impossible to cheat - so only moderators can edit and delete posts in this forum, though I'm guessing the players in here aren't the type who would want to cheat anyway.
Full instructions for rolling dice are here:
http://www.terrypratchettbooks.org/g...mode=bbcode#11
but basically all dice rolls have to be in dice tags - [dice]d6[/dice] will roll one six sided die in your post, [dice]2d6[/dice] will roll two six sides dice in your post and so on.
I hope this is useful.
P.S. have a mess around with it in this thread to test.