Pin Code Search is an Offline Pin Code App from PinCodeLookup. This app lets you search pin codes using state->district->post offices. It also lets you search pin codes and locations directly using search option.
Along with Pin Code Data the app also have phone numbers and address of post offices for some locations. As of now it is not available for all the post offices in the system, it is available for major postal offices in India. Indian Post Office address can also lookup using known pincodes of the particular location.