If you're having problems with a CD burned from an ISO on your Thinkpad, try burning it with another system. I'd tried the standard install but it just sat there after choosing 'Install Ubuntu' at the main menu. The alternate install got further (after encountering a bunch of read errors) but encountered an MD5 error on a package during the 'Select packages' phase. And I tried this with CDs burned on the Thinkpad (a T60p) at different speeds. No go.
After burning the CD with a desktop WinXP system everything worked as normal, and I now have an 8.10 install on a separate partition I'll be updating over the next few weeks to get it up to speed.