Do you use a web cam much? Business meetings? Family or friendly connections? With so many Internet-enabled communications toys these days it was only a matter of time before they found a way to give you a virus by web cam session. This may not be the first vulnerability, just the first I've noticed for MSN Messenger.
It looks like a simple upgrade should get you around the sticky parts. Unless of course you're on a Linux or Mac OS X box, in which case you can giggle and move on now.....