Honestly no clue. At the moment I have no tablet at all, so I don't know the specifics of the Wacom control panel software. Since it is however tied to Ctrl+left arrow/Ctrl+right arrow, it may not be possible to use directly. It's not utterly impossible, though. Using Jeff Almasols KeyEdUp script from the Adobe Exchange pages you should be able to change AE's internal shortcut for this or assign a secondary one and then be able to use those keys on the Wacom. If the script for some reason doesn't work, manually editing your AE shortcut file's ["CCompTime"] section will contain all the relevant key info.
I have my Wacom tablet set so that two of the buttons in the corner are mapped to Page Up and Page Down, which move the current-time indicator one frame froward or backward in the timeline. Instructions for remapping these buttons are in the Wacom documentation.
Thanks guys for the suggestions.
Mylenium - I couldn't sort out the script but Todd, that got it working for me!
For anyone else, page 53 on the Intuous 3 manual tells you how to set it up. After you add your application to the tablet (in System Prefs) select Keystroke from the drop menu and name them whatever you want; page up/down or back/forward.