Well, it looks like I spoke too soon about not having anything interesting going on.
The Exception IM Notifier plugin is just like the regular Exception Notifier by Jamis Buck except that it uses ActionMessenger to send instant messages rather than using ActionMailer to send email.
Just do your usual script/plugin install -x svn://technomancy.us/exception-im and follow the directions there.
Note that you'll only get notification in production mode for obvious reasons. If you'd like to try it in development just to confirm that it's working, replace "rescue_action_in_public" on line 70 of exception_notifiable.rb with "rescue_action".
Anyway, give it a go. Plans for future improvement include AIM integration (so far it's just Jabber) and the ability to fall back on email notification if the user is not online.
Oh, also I found out that Ebby got mentioned in a Linux.com article. It was a pretty insignificant blurb, but it still seems cool by my low standards. (I've never had any high-profile mention but for a quick link on RedHanded.)