Online multiplayer games are available, as well as a single-player against computer.
How to play: http://wiki.openttd.org/Tutorial
If you cannot hit buttons at the screen edge - calibrate touchscreen from the Mouse emulation dialog in the Chnage device config dialog at startup.
Touch the screen with two fingers to cancel current action, if you misplaced a road or a station.
This game is open-source - you may find sources at http://openttd.org/ or at my website.
You can install old version from here: http://sourceforge.net/projects/libsdl-android/files/apk/OpenTTD/
This game is not affiliated with the original Transport Tycoon Deluxe game, and does not contain any content from the original game.