Is there any way to bypass whatever blocks are in place?

Not easily, no. I'm one of the guys who runs a system which blocks that stuff (and controls all the ways you get around it), and there's no way to get past it unless you have the ability to run some kind of a server-side proxy on a server on the exposed portion of the internet.

I've always wanted to invent a server-side proxy with a client-side shim that would do that kinda thing. In theory, it could work for anything (online games, etc.). Haven't gotten around to it.

Oh, and Derrick: If they're blocking MSN, they're probably blocking SSH too.