I tried out aMSN (Delayed response... been avoiding my email inbox lately)
It wasnt as functional as the actual MSN, in means of, it wasnt exactly like it. Actually, it was really different. There were quite a few things that were changed a bit too much for me.
It takes a little getting used to, and it's still in Beta. They're supposed to be adding more features, like voice communications and other regular MSN features in the near future.