I've been working with the ABLE Toolkit from IBM for a few months now, in particular trying to use it as a rules engine for my home grown anti-spam software. I'm using this experience for a paper I'm writing for the upcoming Borland Developers Conference.
If you're interested in learning more about ABLE, specifically on how to get started with ABLE, send me an email message letting me know about your interest. Make sure that you start the subject of the message with the phrase "ABLE:". I'll be glad to send you a pre-release copy of my "Getting Started with ABLE" tutorial as soon as it's ready to go.