Yet another reason not to leave Emacs ... courtesy the console-based CenterIM and a little bit of code in my .emacs file, I can do all my instant messaging (MSN, Google Talk, ICQ, ...) from within Emacs (thanks to Anselm Helbig on comp.emacs for some elisp advice):

I've updated my Emacs setup on GitHub to include the code to set up CenterIM in a multi-term window. You'll want to ensure that your system has CenterIM installed; on Ubuntu this is as simple as:

sudo apt-get install centerim

Note that my Emacs setup is sufficiently clueful to detect if you're running on MS Windows, & not try to start up any multi-term sessions, including CenterIM.