I used the swear by the Way Out Tube Map (swear by in a good way that is). It was a map that showed you where to get on to get off, or rather which carriage to get onto if you wanted to be nearest the exit when you left your London Underground journey. I've actually lost my well worn copy now and for new users it was fairly complicated.
Today there's a brand new app - Tube Exits - launched for the iPhone which takes the principles in the Way Out Tube map and made it a whole lot easier.
Tube Exits' creator Lance Stewart said "I found it frustrating arriving at a station and being at the wrong end of the platform behind the crowds, but loved it when the train would arrive perfectly adjacent to the exit I was looking for. I thought this doesn't need to be put down to chance any longer so created Tube Exits to help solve this problem. And yes, I did go to every station, most in-fact twice!"
Before you ask it does work underground, so you can plan your journey without an Internet connection, and work things out on the escalator or while waiting for the train on the platform.
You can also save your favourite journeys and also access your reverse journeys with one touch. Although with regular journeys you'll probably remember which carriage to use after a while, and I found the map or apps like this, more useful for new journey. Every station on the London Underground (Zones 1-9) is covered and there are already plans for more versions of the App covering different cities around the world.
Tube Exits is available for iPhone and iPod touch on the iPhone App Store. There's an introductory price of £1.79 (40% off £2.99 normal price) so it's about the cost of a single zone 1 Tube journey.
If you give it a try, I'd love to know what you think.