Technical posts from the AVS BBS:
(as long as they last)
Topic: Hacking the Tivo
http://www.avsforum.com/ubb/Forum6/HTML/000790.html
Topic: Upgrading 14hr TiVo
http://www.avsforum.com/ubb/Forum6/HTML/000926.html
Topic: Has anyone tried to boot a PC using Tivo disk?
http://www.avsforum.com/ubb/Forum6/HTML/002584.html
Topic: How I Upgraded My 14 Hour Tivo MYSELF!
http://www.avsforum.com/ubb/Forum6/HTML/001724.html
Topic: Inside a 30 Hour TiVo
http://www.avsforum.com/ubb/Forum6/HTML/000132.html
Topic: Upgrading the hard drive(s) Lets figure it out
http://www.avsforum.com/ubb/Forum6/HTML/001149.html
Topic: Tivo/Linux/Self Upgrades/Research/suggestions
http://www.avsforum.com/ubb/Forum6/HTML/003200.html
Topic: Oddities from the Tivo Linux source release
http://www.avsforum.com/ubb/Forum6/HTML/001764.html
Topic: tivo Linux source code
http://www.avsforum.com/ubb/Forum6/HTML/001698.html
Topic: Software hacking for TIVO (got off topic, not much tech info)
http://www.avsforum.com/ubb/Forum6/HTML/002510.html
Dazzle Digital Video Creator (board for PC that will encode MPEG like Tivo)
http://www.dazzle.com/
All-In-Wonder card for PC does MPEG
http://www.atitech.com/
http://www.ati.com/na/pages/products/pc/aiw_128_pro/index.html
Some limted technical info and comparisons:
http://ourworld.compuserve.com/homepages/elund/ptv.htm
The Linux source code, note that Tivo only uses Linux to boot, after that they completely take over with a new custom OS.
http://www.tivo.com/linux/