You can download a pdf of the TZ3/TZ2 manual from the Panasonic UK website. Same manual describes both cams. There are a couple of differences - the TZ2 is feature stripped. For example the TZ3 allows for auto-braketing, the TZ2 does not. Also the TZ3 has a 3inch screen, the TZ2 has a 2.5 inch screen. I would suggest to study the manual for these things and make up Your mind whether You need those features.

The pages 7 to 9 of dpreview's TZ3 review contains a direct comparison of the two
http://www.dpreview.com/reviews/PanasonicTZ3/ . To me it looks that at higher ISO (400 and 1250) there is a clearer edge to the TZ3 than the comments suggest. Though from experience I would say the TZ3 ISO 400 files are usable for 4x6in printing only. Again have a look yourself.

Hope this helps.