Empire At War map editor
Plus patch to play the maps.
Star Wars: Empire At War fans can now make their own maps and even units - thanks to a new patch and map editor released today.
The map editor, courtesy of LucasArts and developer Petroglyph, allows you to create your own ground- or space-based maps or modify existing ones using all the terrain, space features, buildings, vehicles and characters from the main game.
You can also download a plug-in for 3D Studio Max, allowing you to design new units and import them for use on the maps.
You'll need to install the version 1.04 patch to take advantage of custom maps, mind - as it adds support for auto-downloading them (presumably on map-load). And, obviously, using 1.04 means you can play other people's even if you're not actually making any.
1.04 also implements "numerous balance changes" and corrects issues, "most notably one where capital ships would be invisible during space combat".
You can grab it off the LucasArts website.