I was about to reply with "Sounds like a PocketPC to me", but it sounds like you've already gotten that far.
The harmony remotes have a TV listing service which always seemed useless to me. I don't know if anyone's tried hacking it, and they're not RF anyways. Though perhaps
it could be.
Really though, it seems like you're taking about a PocketPC viewing a php script. I don't know what kind of the windows media player in XP MC has, but it seems doable. Personally though, the usefullness of a remote with 3 hours battery life seems questionable. He's going to need something else for play/pause/channel/volume, and two remotes suck compared to one.
Matthew