1. A system for off-loading telephony connections for a multi-mode phone from a cellular network to a computer data network, the system comprising: a receiver receiving a request for an outgoing call from the multi-mode phone; a controller for determining if the multi-mode phone is reachable via the computer data network; and a bridge being addressed by a first Mobile Station Roaming Number from a pool of available Mobile Station Roaming Numbers for bridging a call between the multi-mode phone and a destination of the request for the outgoing call, wherein the multi-mode phone communicates via the computer data network and the destination of the request for the outgoing call communicates via a public switched telephone network, wherein the first Mobile Station Roaming Number is received from a Service Control Point during call setup.