Take a look at the google webmaster guidelines for information about a dmca (Digital Millennium Copyright Act).
http://www.google.com/support/websea...l=en&answer=58
I would also advise your processor that your sign up page has been copied as well. It may be that your russian has his own processor page and is trying to redirect your traffic to get signup's of his own that you will never be paid for. The downside of course is that customers caught this way will be looking for a refund from you!