Need to move the last person over to domain who doesnt want to move..

Hi..

Im sure some of you have had this before, there is 1 user who just doesnt want to move from onto my domain so its time i played his game…my setup is basic i have a w2003 which is used as the DNS server and a adsl router as default gateway so if you dont resolve with the DNS you cant get on the net..so my question is..can i just tell DNS to query and allow only domain members to get DNS as without that he wont be able to access the internet…if i cant is there any other way to block it..

thanks in advance