David Torno has released an update to his keyboard shortcuts popup script, Shortcut Key Reference. It has even been optimized for CS3 compatibility.
David says:
Looking for a shortcut key in After Effects? Well how about having access to a list of over 600+ shortcut keys without leaving the After Effects environment? Shortcut Key Reference v2 to the rescue. Give yourself an added advantage by learning shortcut keys for most of your everyday tasks. You’re a veteran AE user? Well it doesn’t hurt to have a quick reminder of a valuable shortcut key that maybe you didn’t use enough to memorize. I’ve been using AE for eleven years now myself and I am always finding new shortcut keys I didn’t realize were there.
Shortcut_Key_Reference_v2 has been finally updated and is compatible with CS3, CS4, CS5 and CS5.5. It now includes both the Dropdown List and Listbox versions from the 2007 release in one script. You can easily toggle which version you would like to view just by clicking a button. With the Listbox version, you can find shortcuts faster by typing in the search field.
Download Shortcut Key Reference and read more about the script.