Assign Shortcut Keys to iTunes AppleScripts
Mac OS 10.3 introduced the ability to assign menu shortcut keys to pretty much every application, including iTunes. And including AppleScripts in iTunes' Scripts Menu. Here's how to do it.
(Hey! If you don't want to do-it-yourself, FastScripts from Red Sweater Software provides the ability to quickly and simply add and manage AppleScript keyboard shortcuts. I highly recommend it.)
Step 1: Set Up Your System Preferences
Note: This will only work with scripts that have been installed in your [username]/Library/iTunes/Scripts or [startupdisk]/Library/iTunes/Scripts folder.
Another Note: the instructions and screenshot below are for OS X 10.8, but vary only slightly (and obviously) under OS X 10.9.
Quit iTunes. You can't attach a keyboard shortcut to an application if it is running.
Open your System Preferences and click on "Keyboard" ("Keyboard & Mouse" for pre-Snow Leopard) in the Hardware row. Click on the "Keyboard Shortcuts" tab.
Click on the "+" button to add a new shortcut. In the Application pop-up of the window that appears, select iTunes. Beneath this pop-up in the Menu Title field enter the name of the AppleScript in iTunes Scripts Menu to which you want to assign a keyboard shortcut. Better write it down before you quit iTunes because spelling counts! In the Keyboard Shortcut field press the combination of keys you want to use for the shortcut.

Setting the shortcuts for the Pretend We Played This script in Snow Leopard's System Preferences (although it looks about the same thru Mavericks). The key combination I pressed is Shift-Command-X.
Close System Preferences.
The next time you start iTunes, look in its Scripts Menu. The shortcut you assigned will be displayed adjacent to the name of the Script you assigned it to, just like a real menu shortcut! That's because it is a real menu shortcut.
For more details, search your Mac Help for "Setting custom keyboard shortcuts for applications".
OF COURSE, you can also assign keyboard shortcuts for iTunes' menu commands that don't already have a shortcut, such as "Check for Purchases...", "Export...", "Check for Updates...", and so on.
If you assign a keyboard shortcut which iTunes is already using, you may get mixed results. For example, I assigned Shift-Command-Nwhich is iTunes' "New Playlist from Selection" shortcutto a script and the script fired (the script actually does the same thing as "New Playlist from Selection" but asks for a new playlist name first). But it wouldn't let me assign Command-A, the universal "Select All" shortcut. It also knows what keys you have assigned already, and it will warn you if you try to enter a duplicate shortcut.
As far as using the F keys: I could only get combinations that included Command to work. No problem, though. There are still hundreds of key combinations available.
Sometimes I had to quit and re-start iTunes a second time before the shortcut "took". Maybe that's just my system.
Check out the Missing Menu Commands page for some mini-scripts that work great with shortcuts.
Here are some suggested scripts to which you may want to assign a shortcut:
- Play Random Album v3.1
Creates and plays playlist using tracks from album chosen at random - Update Expired Podcasts v2.2
Update subscriptions which have expired by virtue of being ignored for five or more days - Search-Replace Tag Text v4.1
Perform search-and-replace on text in your choice of tags - Remove n Characters From Front or Back v5.0
Delete characters from the beginning or ending of selected tracks' name, artist, album, comments, composer, or show tags - Player Position to Start or Stop v2.0
Set current track's start or stop time to current player position - Reset Bookmarks to Start v2.0
Reset selected tracks' bookmark position to their Start Time - Whack Current Track v2.0
Deletes the current track from all playlists and moves to Trash - Just Play This One v3.0
Play the selected track and stop - Have a Quick Look v1.0
View selected tracks, PDFs in QuickLook windows
Playlist Assist