Defeating the sploggers

I have a terrible problem with spammers at healthblogs.org. There must be some “back way” they’re getting in! I edited the script so that the activation message comes to me, and there are hundreds! The issue is that I looked on the blog this AM to find that somehow about 10 sploggers had created blogs!

I have captcha installed, but that’s not deterring them at all. Is there a script they’re using to bypass this?

In addition, I added some reg expressions to my banned domains to deny registrations to .info, .ru and .biz. This morning when I looked in there, the entire field was empty!

Is there any help for us? I’m bewildered.

Thanks,
Beth