In a default install, the members pending page will link you to samspade.org - which will give you a WhoIs search. Semi-useful. While there's no MOD for it per se, you can search http://www.stopforumspam.com/ for the IP/UserName/e-mail Address. Its been my intention for some time to write a MOD or something like that, I just haven't had the time.

I started with Snitz around 3.4.04... can't say what was and wasn't in there in previous versions. However, if you're using 3.4.03, you will definitely want to upgrade. There have been quite a few changes and security patches since then.
The announcement hasn't gone out yet, but 3.4.07 is available from our SourceForge.net page. There's a minor issue with new installs and the Access database that comes with the .zip (which is why we haven't announced it yet) but since you'd be upgrading you shouldn't see any issues. Have you added any MODs or made any changes to the code (excluding editing config.asp and any bug fixes/security patches posted here)?