US company Broadbeam has developed IntelliSwitching, a software that provides seamless switching between wide area and wireless local area networks.
The system can automatically detect the Wi-Fi or 2G+ networks available, seize that network according to a user-defined order, and authenticate the user.

London Ambulance is currently testing the software. They switch between 5 networks, using Wi-Fi in their depot to download maps to get to a patient and resort to wide area when out of range to convey vital patient data back to the hospital.
Before IntelliSwitching, about one minute could pass to give the call details to the ambulance by voice, after that the crew may have needed to look on a map to find the destination. Now it generally takes two seconds for all the call details to be dispatched to the ambulance, and the computer in the vehicle tells the navigation equipment where to go.
Read InfoWorld.