This article describes an IDS that's tailored for IIS. May
be a good addition to major IDS solutions as most have
glaring weaknesses.
They have a beta program.
http://www.pwicorp.com/ASA_IIS_BetaOverview.html
I found them through a press release, which talks about
the underlying Adaptive Security Engine.
http://www1.internetwire.com/iwire/release_html_b1?
release_id=49690