Sam, I had the same problem using MT I did not like having to do the manual deleting.
I moved to Wordpress and installed 2 anti spam plugins that automatically intercept the spam and prevent them from doing any thing.
The best is they don't send an e-mail saying when a spam was caught.
The 2 are Spam Karma 2 and Referrer Karma, both by the same person.
If you ever decide to move let me know and I can point you to the howtos to make the move.

.. I've got a sharp knife, Sambo....

Call the DAWG on TV, he is full of shit, but gets the job done, Cat

I went through, and am still going through that tb and comment spam. I too, have Word Press, with Spam Karma 2 installed, and it's a lot less "headache" to eliminate the assholes from the cotton, but, I find that using it, damned near seems to send some folk's directly into the "moderation" queue... kinda pisses me off. I'd like to see a feature where I could go ahead and add somebody to the "white list" so their comments wouldn't get stuck in the queue.... Yeah, that Dawg fella is pretty funny now. Cat's right 'bout that. 'Cept I don't think he'd do what you want done to 'em. Everybody I've seen him work on, just goes to jail... Not killed dead.

I went through, and am still going through that tb and comment spam. I too, have Word Press, with Spam Karma 2 installed, and it's a lot less "headache" to eliminate the assholes from the cotton, but, I find that using it, damned near seems to send some folk's directly into the "moderation" queue... kinda pisses me off. I'd like to see a feature where I could go ahead and add somebody to the "white list" so their comments wouldn't get stuck in the queue.... Yeah, that Dawg fella is pretty funny now. Cat's right 'bout that. 'Cept I don't think he'd do what you want done to 'em. Everybody I've seen him work on, just goes to jail... Not killed dead.

The cure:

Captchas.

If you go with MT 3.2....it has a Spam blocker. If not, the earlier versions have a plug in where you can close comments and track backs.

Hang in there sweets...there are answers out there but I agree. If you find the spammer? Can I be the first one to hurt them?

You can't shut down!

I got em too. But look at the bright side. Now we're getting 50 google hits a day from peeps searching ebonic elephant mating rituals. Ok, so my phrasing is a bit off...