You could use any IR remote you like with this. I used to use one before I got my ATI Remote Wonder (which I recommend highly). An irman with Girder will let you use any IR remote you have lying around, or you could go buy a universal remote at your local electronics store, and use the built in codes. You could use the different devices on the remote to control multiple areas of the MythTV box.

But yeah, I recommend the Remote Wonder. I think there's a version with IR in addition to RF. Regardless, I recommend Girder, though many people here dislike it. I've used it for everything from myHTPC to Winamp to Windows Media Player to mplayer to controlling my X10 devices and making them turn on and off at sunrise and sunset.