Panther has a cool feature that allows you to set keyboard shortcuts for pretty much any application, including iTunes. However, one thing I discovered is that you can set keyboard shortcuts to the AppleScripts in your iTunes Scripts Menu. Simply follow the instructions in Mac Help for setting keyboard shortcuts (search for "Setting custom keyboard shortcuts for applications"). Instead of entering the name of a menu command, enter the name of one of your scripts in iTunes Scripts Menu. Voila!

Here is a short tutorial (http://www.malcolmadams.com/itunes/itinfo/shortcutkeys.shtml) on how to do it.