Another great idea from Old Blighty.
The Knowledge is a phone service, manned by off-duty cab drivers. They can give you directions to get to anywhere you need to be, where to find something or the best place to find a parking spot near where you're going.
Again, this is a fantastic idea. I hope the cabbies in Sydney start a similar service.
In case you don't know, London cab drivers are required to pass an onerous test called The Knowledge in order to get their licence. Hence, the name.