If you mean like an MSN Client for Linux?
Yeah there's a few...
There's GAIM (Don't know alot about it, except it's multi-protocol, which is a good thing
Then there's aMSN (Or Al's Messenger.)
Personally, I use aMSN, I think it's the best of the two.
I believe check http://sourceforge.net/projects/amsn/
or something similar?
Either way, just go to sourceforge and search for aMSN...