Myth2Ipod lets you set your recorded TV programs to be transcoded for viewing on the iPod. The best part is that it also builds a php page which you can point iTunes at, and it treats your TV shows like a Video RSS feed. So, iTunes goes off, downloads new ones, keeps them labeled properly, etc. – just like a regular podcast. That way you can just drop your iPod in, download all of the shows you’ve recorded since you last sync’d, and go.
Right now it’s not making use of MythTV’s commercial flags, so your recordings still have commercials, but I wouldn’t be surprised if that was in the works. Very cool. Also good if you’re about to get on a long plane ride (as I am) and have a bunch of recordings sitting on your PVR that you hadn’t gotten around to watching.