1. A system for planning and managing real-time postal delivery work, the system comprising: a receipt and sorting work quantity information acquiring and transmitting block that sorts quantity information by types after a post office and a mail center perform receipt, collection, and sorting work; a postal logistics operating block that transmits, to each delivery post office, the quantity information from the receipt and sorting work quantity information acquiring and transmitting block to use as calculation criterion information of a scheduled delivery quantity for formulating a real-time delivery plan; a real-time postal logistics delivery planning and managing block that sorts the quantity information from the receipt and sorting work quantity information acquiring and transmitting block, performs calculation of delivery-zone-based and delivery-route-based scheduled delivery quantities, detection of an excess of delivery workload, calculation of the quantities of entrusted and residential delivery zones, and calculation of the quantities of delivery-zone-based intermediate depositories, generates a delivery route in consideration of a criterion date of special mail item traffic quality and then calculates a general mail item delivery quantity, and provides a postman with information about the postal delivery work; and a delivery and collection work information acquiring and transmitting block that registers a delivery location and a delivery quantity through barcode or RFID tag recognition at a delivery completion location during the postal delivery work with reference to the delivery route and the quantity information generated by the real-time postal logistics delivery planning and managing block, confirms a collection box and registers information about a collection quantity at a delivery location at which collection is to be performed, during the collection work, and transmits the registration results to the real-time postal logistics delivery planning and managing block.