Parmesan is great. It looks and feels so polished that you only realize it's an early version by the lack of certain features.
hEngelia:
MSN audio is similar to SIP. There is a service called gtalk2voip that redirects MSN calls to VOIP accounts. I wonder if there is any scope for doing that that in a client. i.e client advertises it is available for chat, and when it receives a request forwards it to a SIP account. And if the chat button is pressed it initiates a call to the sip account and when answered it connects it to the MSN account.