This Simple XMPP client for Ruby looks like a great way to get some IM loving into an application. I’d love a monitoring system which used IM to alert me to failures. Since IM is not exactly a perfect medium, sending a copy of the message via Email for critical alerts is probably a good idea too.
Could be fun to ask your monitoring IM buddy “Status?” and get a status report. X Emails delivered, Y Emails rejected, Z books looked up on Booko.