I don't have a Tivo, but those who do who haven't already done this might appreciate the 30-Second DVR Tweak to Speed Up Commercial Skipping. Thank goodness the MythTV has this all built in from the get-go :)
Dude... that hack ROCKS. My TIVO works AWESOME now for zipping through commercials!!
Thanks!
Happy to help! Like I said before, I'm shocked that Tivo people *don't* have this already :)