Mobile phone giant NTT Docomo and Tokyo taxi service Tokyo Musen have teamed up to provide that rarest of things in Tokyo -- free Wi-Fi.

Some 820 Tokyo taxis have been installed with the technology on a trial basis until the end of March 2011 and 100 of the taxis also have PSP Go devices on board so that users can play games while going for a ride.

The trial aims to find out what the demand is for Wi-Fi while on the go, and could see the service expand after March.