A method and system are described for use in a portable electronic device that includes a wireless local area network (WLAN) subsystem, a cellular packet data subsystem for communicating packet data, a cellular voice subsystem for communicating cellular voice information, and a processing subsystem. In the described embodiments, the WLAN subsystem establishes a connection to a WLAN and the WLAN subsystem then determines the signal strength of the connection to the WLAN. Then, on condition that the signal strength exceeds a threshold, the processing subsystem selects the WLAN subsystem for the communication of packet data to and from the portable electronic device, and puts the cellular packet data subsystem into a reduced power state that reduces the power consumption of the cellular packet data subsystem. Packet data is then communicated to and from the portable electronic device using the WLAN subsystem while the cellular data subsystem is in the reduced power state.