Well, I don't know if Pocket PC 2002 added the capability or not. My understanding is that the only way to do it is to take control of the com port as a driver of some sort, which is then notified of power events. An excerpt from the topic "Programming in the Suspend State":
WaitCommEvent Waits for a communications event to occur. Serial, Infrared Data Association (IrDA), or PC Card storage devices can return EV_POWER when the device resumes operation.
Dan East