This photo is a screen shot from my iPhone using the Google Earth app. It can geo-locate you (see the blue dot) and then track you in realtime. I love the development of useful software that helps you based on knowing where you are.
Jim White, who us driving me today, put me onto the O2 traffic line (dial 1200 from any O2 phone) and you get traffic info based on where your phone is calling from. Cool.