Quick Reference cards are a big help. But while running some laps with Flash I got tired looking constantly down at my card then back to my screen. I finally decided to develop my own keyboard shortcut system. My goal was to create a handy tool that I could place above the application I was using. It had to be somewhat unobtrusive but still easy to read.
Underlined words link to a third level of shortcuts.
If I am editing frames I set my tool to display the Edit - shortcuts. Of course my ultimate goal is to design in Flash without it. But for now it's a handy reference. The tool is downloadable. Check it out and let us know if it's useful.