1. A wireless network device, comprising: a controller; a wireless transceiver coupled to the controller and operative for communications in a wireless communication network; memory for storing an application program; the controller being adapted to execute the application program for controlling operation of the wireless network device; the controller being further adapted to receive, through the wireless transceiver, an instruction which causes the wireless network device to operate as a client in performing an over-the-air download (OAD) procedure for receiving the application program from another wireless network device which is operated as a server in the wireless communication network, and to operate the wireless network device as the client in performing the OAD procedure in response to such instruction; and the controller being further adapted to receive, through the wireless transceiver, one or more instructions which cause the wireless network device to operate as a server in performing the OAD procedure for sending the application program to another wireless network device which is operated as a client in the wireless communication network, and to operate the wireless network device as the server in performing the OAD procedure in response to such instructions.