Here is a trick you may already know. If you hold down the apple key and click on the Tivo Desktop icon in system prefs, it adds a video tab to Tivo Desktop. Files(must be mpeg-2) that you put in the Tivo Tv shows folder in your home folder will show up in the now playing list on your Tivo in a folder titled "Your computer name". When you select to play these files, they will be copied onto your tivo. I tried this and it worked great. I am now going to digitize my old home movies using my Miglia TVMax. This feature combined with the Amazon Unbox deal will probably keep me from buying AppleTV. Plus I would need a new TV for AppleTV.
Getting Your Tivo and Macintosh to Talk