If you're a little bit scared and confused about London because you've only seen it on TV and the map seems quite hard and where on earth do you get tickets from? -- here's something that might help. An anxiety-reducing interactive map so you can plan your trips from afar, then interchange like a pro without stopping to squint at the signs and holding up all the serious people.
It's the Tubermap, and all you do is click on a station and draw a line to another one. It then colours it all in and makes it look nice, also providing a short key list of stations, showing where you need to change and estimated journey times between each interchange. It even includes the Emirates Air Line, should it not be windy and you fancy dangling over a bit of East London.