[tkjames]

If you have Vista, Active Sync is Windows Mobile Center. Open that, then click on "Mobile Device Settings".
Click on "Change content sync settings"
Unselect the "email" option, then save.
Sync your phone, and Outlook should be gone.

This is all based on the post by Aiverson. Note, however, that you DON'T have to delete the partnership first for this to work (or at least I didn't).