On Saturday, August 2, developers for MegaMek released a preliminary version of a map editor feature for MegaMek. This will allow players to edit their maps prior to playing, so that they can play on a map they modified. This highly anticipated feature is in the earliest, debugging stages.
MegaMek is a great way to play the BattleTech game online with some friends. You just have to have a device that runs Java, and download the free client. There are numerous programs that run with it to create campaigns, online worlds, and more. Check out MegaMek and give it a spin.