The Adobe Shortcut App is a new AIR application that's a database of all of the keyboard shortcuts for all of CS4, all in one handy place.
Todd Kopriva reminds some of us that "To see all of the shortcuts, be sure to click All Categories. The default Essentials view just shows a small subset"! Todd thinks that "the information appears to be identical to that in the Keyboard shortcuts section of After Effects Help." For information on editing keyboard shortcuts and scripts (and scriptable AE commands without shortcuts), see the KeyEd Up script by Jeff Almasol.