londrum - 6:48 pm on Sep 20, 2007 (gmt 0)
if you can still FTP your site then back it up quick. and then delete the whole lot from the server.
there's not much sense in letting him have it. maybe stick a robots.txt file on there as well to get it de-listed from the search engines. if you block the entire site in robots.txt then you can use google's url removal tool to wipe it from their index for 6 months.