In any case, pyTivo allows me to push media from my computer (vidcasts, podcasts, SageTV recordings, etc.) back through the TiVo.
The bad news is that the program actually has to load the media onto the TiVo. The good news is that you can start playing it a few seconds after the transfer starts (good for large vids!).
I did have to monkey with the config file just a bit. I had to enable the beacon and change it to the broadcast address for my network (vice 255.255.255.255). Note: the Cheetah Namemapper warning supposedly can be safely ignored.
In any case, I can now watch vidcasts on my TV without having to use the funky podcast client built into the TiVo interface. Even though I can play music through there, I don't have a decent sound system connected to that TV so I probably won't use that one much. Also, lets not forget the ability to pull files off of the TiVo with the web interface (backups!).