I had the same problem. These scumbags ruin everything, Guestbooks, Message Boards, etc. I changed my GB to manually apporve all posts to it. What I did was add a field to database called show_entry. I move a 'n' to it when a new entry is submitted. Where the entries are viewed, I only show those with a 'y' there. The 'y' gets put there when I approve the entry manually. My GB isn't that busy so it's not a big deal. I wrote a small php script that shows me the entries with 'n'. On the same page I can approve or delete them easily. I also took away the Submit on the first page forcing them to Preview first. Works pretty well. Would love to have just 1 of these guys alone for about 5 minutes. They'd never be able to spam again.