In an unusual move for TiVo, they released Desktop v2.4 (PC) software two months ago as a public beta. Looks it went GM a few days ago, though without full support for Vista. (If you can get it to install, try XP compatibility mode.)
TiVo Desktop 2.4 adds support for additional PC folders and offers HD photos on the Series3 (which I never got to work). Series2 owners who purchase a Plus license ($25) get the ability transcode TiVoToGo transfers for PSP, iPod, etc playback. The same Plus codec pack can now be used in reverse to prepare and transfer select video (.wmv, .mp4, .m4v) to your Series2.
Other TiVo desktop/transfer options (free, for the geeky) worth checking out include Galleon, TiVo.net, TVHarmony AutoPilot, and pyTivo.