0. open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal
1. sudo add-apt-repository ppa:ubuntu-wine/ppa
2. sudo apt-get update
3. sudo apt-get install wine1.5
4. sudo apt-get install winetricks
5. Download CS2 from Adobe, and then just doubleclick the .exe installer, put in serial number as usual, and launch from Applications > WINE > Programs.
Remember you need a proper CS2 licence.
And acknowledged by official Adobe policy as being OK:
"FEBRUARY 08, 2008
Wine offers improved Photoshop-on-Linux support Wine, the open-source compatibility layer for running Windows programs on top of Unix-style operating systems, has been updated to offer improved support of Photoshop CS2. Using the latest updates (of which another has been posted today), it should be possible to run PSCS2 for Windows on top of Linux."