ActiveSync is the software on the mobile side that handles syncing and it's made by Microsoft. Other platforms license it too-- your co-worker's Symbian phone, for instance. You could use OWA to access your email but trust me, Echange is the best and most complete way and should work fine since your company uses Exchange. If they use Exchange Server 2007 or later, then push email will work as well (otherwise the device will check email on an interval that you specify).
-------------------- Lisa Gade Editor in Chief, MobileTechReview