When Demand Planning feature is enabled and the Replenishment Method is Time Phased, the Expected Receipt Date is found as one of the columns on the Purchase Order form. The Expected Receipt Date is computed based on the Lead Time set on the Item record. It will be computed from the date of the purchase order.
Purchase Order date is 9/30/2014
Lead Time on the Item record is 5
By default, the Expected Receipt Date column will show 10/5/2014.