mac newbee question.

Weed is right about the main application files - just dragging to the trash is quickest.  There are also some files in the System folder, how many depends on the manufacturer.

There's almost always a preferences file in the Preferences folder, and often some other support files.  Unless you're really short on drive space, these are rarely of concern.  The main exception is when an application has installed an extension, such as the Microsoft apps.  These have system-wide effects and may need to be remove (Adobe PS doesn't have any that I know of).

There's a nifty utility called Spring Cleaning that helps clean up the System folder, getting rid of unnecessary files from deleted applications.  Great for anyone who doesn't want to do it by hand.  It's from Aladdin and runs, I think, about $49.

most installer will also have an uninstall feature. Just pop in the photoshop disk, start up the installer and there should be an option on the pull-down menu for uninstall.

To clean install a program...open your extension manager, select OS 9.X ALL and restart your computer, install the program.  Go back to extension manager restart the system.  If the system starts up fine, then select/return system to My Settings, restart the system.  By installing 3rd party programs this way, you know if the application conflicts with any OS extension. After restarting, if there is any issues, then you know an extension conflicts with another 3rd party application.

http://www.mac.org/utilities/yank/

This will do it. But be careful.

there should be an install log for photoshop somewhere, either in the main directory of the hard drive of in the adobe photoshop folder. this log tells you where every single file was put on your computer by the photoshop installer.