I use Irssi for IRC’ing on the Mac, because it is simply the best client out there (except for the fact that it only has perl scripting support).
Recently I found myself wanting some kind of notification thingy, which would allow Irssi to discretely notify me when when something interesting happens on IRC. Irssi, being a console app, doesn’t really have any way of supporting this, except through the use of plugins. So, I had pretty much decided to dive back into perl and write up a simple script for irssi, utilizing the Growl for notifications by means of the Mac::Growl package.
As it turns out, someone else already did. And not only that, someone else took the time to explain in meaningful detail how to get the whole thing working. So, now I have growl notifications whenever someone sends me a private message or says my name in a channel that I have joined.
I like good software.