That's pretty durn cool. I've been a long time user of Mozilla/Firefox, and I love the keyword stuff. I have a few setup myself, but I never thought of using a local perl script to leverage the ease/power of Firefox for such an app. This specific app is not very useful to me though, as I'm a Linux user, plus I don't do much IRC or IM. But I'll definitely remember the perl/firefox one two combo for future stuff. :)
ages ago I wrote a similar script for searching my browser history and presenting the results on a webpage using firefox keyword bookmarks. Very similar as a matter of fact...just dug through my browser history files instead of my chat logs :-)