Yes, there's already a topic, but it's over a year old and has only one page, so I'm making a new one.
http://www.freeallegiance.org/Allegiance is, in essence, an RTS, with one major difference: most of the units are players. As a commander, you play the RTS role, which has very intuitive graphics.
As a pilot, however, it's a whole different story. Allegiance is an RTS as the commander, but there is only one commander per team--to put this into perspective, the max player count is usually 100. The other 98 are filled by players, who can be commanded as units through a simple and very well-done command system. Here's a good tutorial:
http://www.freeallegiance.org/FAW/index.php/Quick_Crash_CourseOther info can be found on the wiki, much like Dwarf Fortress.