About Comment Spam

Hi,
some of my freinds and me are using WordPress, and since a few days we’re the target of Comment Spam. those who experienced that know it’s really annoying.
I’m not developper myself, but I’d love to see a hack, or an extension, or anything like that, that could prevent spammers from posting. Something like IP banning …
I heard about a MT extension that could stop a list of IPs, and that list was updated weekly … maybe someone could use this system (and even the same list system) to make it work ?
thanks a lot =)