I've successfully installed Debian Lenny (with a sid 2.6.23 kernel) on my ThinkPad T61. Here to contribute what I can - don't hesitate to shoot me a line if you have a question about how I did things. Hope to make a HOWTO at some point; for the time being I point you to the excellent instructions at klabs.be:
Good luck, and happy hacking!
Kyle Barbour 09:51, 13 February 2008 (CET)