The first thing you need to do is Zipper
your DirecTivo with a PC.
MRV is done between Tivo's - so no computer is required.
Everything else listed below is done on a Mac.
HMO stuff supposedly can be done with JavaHMO
. I fiddled with JavaHMO for awhile ago but couldn't get it to work on my Mac. I think the problem was this program was designed to work with an older version of Java that wasn't on my Macs.
The best program to watch Tivo shows on your Mac is Tivotool
TivoWebPlus is built into the Zipper - so you can access your Tivo from any web browser
Lastly there's an interesting Yahoo widget posted at Widgetgallery
called OzTivo that works great on both Macs and PC's.