First Off The Tube helps you board the Tube, Overground, and the DLR in order to be closest to your exits and interchanges at the chosen station. It incorporates a detailed database of each and every exit and interchange found on the Tube system and works perfectly well while you're underground as it needs no internet connection or GPS information. You can search by line, or just by the station name to find the station you're looking for.
The app also provides information on the closest stations to a number of London's tourist attractions and the Olympic venues. Enjoy!
ps.: if you have queries as to how to use the app or comments, do drop me an email, especially before leaving negative feedback. Thank you.
pps.: People, this app is not related in any ways to Tube Assitant or any of the others. I don't care if your v6 android phone can't work with TA, it's not my app. Contact the author of that app if you have issues with it.
pps2.: I know the design is outdated - there are numerous screenshots and a video on what it looks and how it works, if you find it okay, buy the app, if you don't, then don't buy the app only to tell me it's ugly.