I have a n800 that is connected 24h to my server pc through remote desktop.
There a 3 ways you can use it with mc:
1. Use mc's upnp server. This works great with Nokia's mediastreamer app. Also the more slick Canola interface will soon support upnp too. This will only give you playback on the Nokia only as for now mc can't acts as a upnp client.
2. Use the Nokia's browser to control mc with xptunes.
3. Use remote desktop or vnc to control mc directly on your server. This actually works pretty good as long as you dont show any video content on the device itself.
I do not have that much experience with the above as mine is mainly used to control my squeezeboxes. I guess if you want to use it as a upnp client it will work ok. If you want to use it as your main controller to cotrol mc zones you might be disappointed.
peter