http://www.ebay.com/gds/How-to-find-...8527954/g.html
I think anything before the PW1 can be jailbreaked. After that, watch out! Personally, I think I'd get a cheap soldering iron...If you decide to get a new e-reader, I'd personally recommend the Kobo H2O. I have an Aura HD, and the extra size is luxurious, a real upgrade. Also it can be hacked to death and has an absurd amount of font options. But be aware, you do have to frig around with it a bit to get it just right. It's not as easy to use out of the box as the Kindles. The new Glo HD is all right and well priced. It's pretty comparable to the PW2, though I think the light doesn't go down quite as far.