Every time I need to set an environment variable in Mac, e.g. JAVA_HOME, GWT_HOME, I always end up turning to Google to find out which file I need to edit; because there are just so my plists! (the file you are meant to edit is here, ~/.MacOSX/environment.plist, and yes create the folder and file if it doesn’t exist and  you will need to logout and then in to apply the change)

This time I stumbled across RCEnvironment, by Doug McClure. This has to be the most useful preference pane in existence. It adds a preference pane to System Settings that lets you easily add environment variables.