Tremote lets you use the MC interface on one machine (client) to control the playback on another (server)
Run Media Server on the server.
Configure Media Network on the server. It can generate an Access Key.
On the client, do File/Library/Library Manager and Add Library. Enter the Access Key on the client.
Now you've loaded the library of the server on the client.
Under the client's Playing Now, the remote machine (the server) should show up. You can drag content to it or just click on it. Everything should then play on the server.
Here's a thread with more information: http://yabb.jriver.com/interact/index.php?topic=52261.0