This hot new software allows you to set up your PC as a fake TiVo that your real TiVos can stream from.
http://tivoserver.sourceforge.net/

This is a killer app. I played with it very late last night, so I didn't get much time to experiment. I did, however, get it working pretty quickly. It will transcode video on the fly to serve to your TiVo. The only thing I had on my laptop was a 30 second XviD I made from a commercial. It worked!

Some notes so far are:

• It seems to work on Linux a lot better than Windows (I am using Windows at the moment).
  
• I initially tried the 0.4 release, but I was missing the dependencies
  
• The 0.4 Windows release doesn't seem to pay attention to some command line arguments (such as where to look for files to serve). This was confirmed somewhere on the Deal Database Forum.
  
• 0.4.3-a2 was tried and it has a proper Windows installer which contains the dependencies. It runs in the task tray and you're unable to set any preferences at this time, but it works!
  
• 0.4.3-a2 looks for videos in C:\Documents and Settings\Your Name\Application Data\video. This can't be changed in the Windows version as far as I can tell. In this way, the Linux version is much more mature.

This program is something I've been wanting for a long time and it's finally here! I'm sure it will keep getting better, but even with its limited configurability now, it's pretty f*cking dope!