You can run this AppleScript from anywhere, just launch it Ð its called Street Spirit Fade Out. It ought to run under any OS that runs iTunes, but I've mostly tested it under OS X 10.1. To put it to use, you can simply double click it... If you want to make it more useful, put into iTunes' Scripts folder. To get there, you should open up your Home folder, and then open up the Library folder. You should have a folder in there named "iTunes" (no qoutes), if you don't Ð make one. Inside the iTunes folder, create a folder named "Scripts" if it doesn't already exist. You should put Street Spirit Fade Out inside that Scripts folder. Now, when you run iTunes, you ought to see a little Script icon at the end, next to help. Select Street Spirit Fade out from there to run it. Simple. Personally, I like having access to it from anywhere in OS X, so I got Apple's free Script Menu utility and then I just put my AppleScript into the Script's Folder (which you can open from the Script Menu utility. Apple explains this better than I will).
Mac OS X 10.2 supports the Applescript shutdown command, and now SSFO does too. So rock yourself to sleep and save power too.