Mini-Chat is installed. It may require some tweaking of the settings before we get it right. It looks like a well-designed extension, though it’s certainly going to suck up some server resources.
I was thinking more of a way to send an instant message straight to someone if they are online at the same time as you, like a little popup in the corner of their screen. Like a true IM instead of a communal chat box. Just a faster way instead of the private messages option.
The PM system should do that. The catch is that there are people that have the site open, but minimized. They won’t know about the message unless the maximize the site again.