I've written a Mac OS X application, Remote Remote GH for MythTV, to control the MythTV frontend (version 0.19). The basic idea being controlling MythTV running on your home theatre computer from your PowerBook on the couch over your home wireless network.
http://web.mac.com/grhowes/iWeb/Gene...mote%20GH.html
I had posted this last week on the Linux Chat board, but someone suggested to me to post here as well.