The AAFID2 system is an IDS based on agents written in Perl. Check it out for their framework.

I'm just getting to know more about agents now, and coming back to Perl scripting after a long time (I did one VERY simple script a few years ago). Right now I'm writting a Perl version of an old kids entertainment program I saw years ago :)

Oh: Links to AAFID:
http://www.cerias.purdue.edu/homes/aafid/

Come to think of it... its creator might actually end up reading this.