OpenTTD 0.7.0 brings you, amongst other things:

    * Reworked order system (conditional orders, have both non-stop and via instead of one of the two)
    * Ability to have much more engines
    * Path based signals
    * AI framework giving everyone the ability to write his/her AI
    * Downloading of AIs and graphics from a central server (only when author wants to)
    * Non-water map edges
    * Initial support for right-to-left languages like Arabic and Hebrew
    * Increase or removal of several limits: window size, number of windows, network clients (now 255), companies (now 15)
    * Six new languages (Arabic, Hebrew, Indonesian, Latvian, Luxembourgish, Welsh)

OpenTTD is an open source clone of the Microprose game "Transport Tycoon Deluxe", a popular game originally
written by Chris Sawyer. It attempts to mimic the original game as closely as possible while extending it
with new features.

OpenTTD is licensed under the GNU General Public License version 2.0. For more information, see the file
COPYING included with every release and source download of the game.

http://www.openttd.org/en/