I have noticed a new annoyance on MSN Messenger. A contact will say something along the lines of:

news:Your.buddy.sent.you.a.cool.Wink,.to.get.it.click
news:Your.buddy.sent.you.a.new.Nudge,.get.it.with.the.new.SweetIM

Followed by a link to the site of sweetim.com.

Although at present I do not believe this to be a virus. Just an annoyance, and a company trying to make you download their version of the MSN client. Personaly I find these things very annoying and tend to block contacts that use them on me. I would recommend staying away from this one unless you want to be the one to annoy your friends ofcourse...