It's back up at http://www.adobe.com/downloads/cs2_downloads/index.html along with serial numbers and no registration necessary.
Adobe did say that this is an archival version only intended for people who have already purchased CS2. It's not a free giveaway.
Photoshop CS2 is the only app in the suite that we've ever tested and supported. I did download and install the Photoshop CS2 .exe from their site and go it to install and run.
The old problems of Photoshop's mini toolbars not working still exists in Crossover 12. A workaround is to open the Wine Config control panel of your Photoshop CS2 bottle, go to the Graphics tab, and uncheck Control & Decorate windows. The window layout will act weird, but you can at least use the buttons on the toolbars. Mac users can also try turning on the experimental Mac driver under the Advanced tab which seemed to help as well.