A mobile telephone gateway and communication routing device (MPG) (121) disclosed by the present invention is coupled through an electrical signaling transmission medium with a mobile telephone (100) operative on a first communication network in accordance with a first communication protocol, for adding communication capabilities through at least a second communication network in accordance with a second communication protocol. A mobile communication system (150) is disclosed, comprising MPG (121) placed in-between mobile phone (100) and battery (118) and Subscriber Identification Module (SIM) card (117). MPG connects to the SIM interface of mobile phone (100), using which it wraps SIM functionalities and controls call management. It connects to the data/signaling interface of mobile phone (100), using which it communicates with it, while communicating with the second network using another communication means. It may optionally connects to an accessory device interface of mobile phone (100) such as a Terminal Adapter/Terminal Equipment (TA/TE) or a USB OTG interface, thereby enabling communication between the mobile phone and wireless data terminals of the second network. In a preferred embodiment of the present invention, a MPG is provided for use with a mobile phone operative on a mobile communication network such as GSM, adding communication capabilities through a wireless communication network such as Bluetooth or Wi-Fi. Furthermore, gateway applications are provided to facilitate or support communication through at least the second network in accordance with mobile web protocols and technologies such as Mobile IP, mobile SIP, and mobile VoIP.