Basically, you install the Tivo Desktop software on your computer. You choose a folder for video. Then any video file you drag into that folder is transferred to the TiVo.
With the current v2.5 software, there is no way to organize recordings that are transferred to the DVR. TiVo has announced the v2.6 software coming in March (a few weeks) that also adds the ability to transfer recordings and any subfolders. The v2.6 software will also add official support for high-definition videos in all major formats. With the current software, you are limited to sending MPEG-2 HD videos.
Does anybody know of any PVR's that you can save your own video files to?
The Archos TV+ works as a DVR, a file server/streamer for media content to and from a PC, and it offers an opera browser to boot.
It's possible to mount the TV+ as a drive on a PC via a usb cable or via a local network, either ethernet or wireless. Video and other (audio, photos) files can be copied across the connection both ways.