Please see post 7 for latest release of new Boxee Web Remote 0.1 BETA
DOWNLOAD LATEST VERSION HERE
Update (10th Nov 2010): New version coming this weekend!
ORIGINAL POST BELOW (For reference, information not relevant for latest version)
OK so I have been all over the forums trying to find a way to control my Boxee from another PC primarily, but also from any device with a web browser.
After some research, I found an iPhone web interface which when placed into the Boxee, can be accessed by any device with a web browser. I may look into editing it so it looks better on a large PC screen but for now its much better to use than the extremely simple 'web remote 0.4' Having said that, the basic interface of web remote 0.4 is useful as this interface doesn't seem to have much in the way of controls, more of a browser and player of your files. It doesn't have pause/play, etc as far as I can see.
Download this iphone web interface that I found after reading this post: DOWNLOAD
Unzip the iPhone folder into your Boxee directory 'web' folder. For example, for windows, you would unzip it into 'C:\Program Files\Boxee\Web'
Now simply launch your device/PC with a web browser and navigate to:
Where BOXEE_IP is the IP address of your Boxee (E.g. http://18.104.22.168:8800/iphone)
I only take credit for my instructions and discovering how to do this. I am not a coder, just a persistent fiddler!