The Transportation and Ticket Center is next to the Poly and across the bay from MK (the monorail and boat to MK run from there. The MK parking lot is the lot that is outside the TTC. You get there by just following signs to the "Magic Kingdom."
and make sure you show them your parking paper for your resort at the toll booth so you dont have to pay the parking fee (onsite guests get free parking @ the parks if they choose to drive)
ENJOY YOUR TRIP!!!!!