Installing this now… I’ve been pretty lucky on the spam front since my move to wordpress, but this is a great sounding tool to prevent repeat attempts.
This plugin adds a “Delete comments as spam” button to the mass editing of comments page. When used to delete unwanted comments, the email address, url, and IP address will be added to your spam words list (SWL). Future comments matching any of those items will automatically be moderated. [Kitten's Project Blog]
I had an issue getting this to install on my 1.3 pre-alpha system… probably related to some DB changes that occur in each update. Hopefully I’ll have this running soon.