Walk It

Following in the footsteps of Transport for London's excellent journeyplanner, which makes pulbic transport so much easier when you are using an unfamiliar route, is WalkIt.com.

They only claim coverage for central London, but I've checked out as far as Archway and got reasonable directions. It recommended the exact route I take to work and while I wouldn't take their suggestion to my old office (I'd take a scenic route to avoid walking along the Holloway Road), it is probably the most direct way and easiest to follow if you don't know the area.

They give estimated journey times depending on your walking speed and as a bonus they calculate how many calories you will burn and tell you how much CO2 you've saved by not using a car or bus.