Check out
www.netremote.org. You can use Girder (free), NetRemote (free), Media JukeBox (approx $25), and a USB UIRT (approx $55) and get on heck of a system set up....
You can also install Netremote on a PDA using WiFi and have bidirectional wireless non-line of sight remote control via the HTPC (home theater PC)...
The is a link for a foum on NetRemote site... do some reading, you may find what you need. HTH-Carl