A designer I follow linked to this article in her twitter feed yesterday: http://gizmodo.com/5973730/grab-photoshop-and-cs2-for-absolutely-free-right-here - apparently Adobe is making available the downloads and serial numbers for all the parts of Creative Suite 2, which includes Photoshop CS2, InDesign CS2, & Illustrator CS2. There's some question about whether Adobe intended to make this information available to the public at large or just to people who had previously purchased this software, but Adobe is well aware now that this information is publicly available and has not put the page behind password protection or even put a notice on the page itself that these downloads and serials are only for those who have previously purchased CS2. Who knows why companies do what they do, there are so many layers of marketing and PR that "mistakes" are sometimes savvy marketing moves in disguise. This could be a clever way to get folks hooked on Photoshop and then once they love it they'll think about the fact that the copy they have is 10 years old and some will want to upgrade.
At any rate, the downloads work (at least for Mac, I can attest to this) and the serials are legit. I know there are a couple of people who are using GIMP and PSP and would love to have PS but it's out of their price range, so I wanted to make sure you guys saw this opportunity.