That video up there should be more than sufficient in explaining what the mod is all about. More or less, it takes the rock solid multiplayer of Modern Warfare and tosses in a whole lot of Star Wars fun.
The new sounds for the blasters and the ships alone sent chills of "that's so effing cool" down my spine. Black Monkeys is the group responsible for this thing, and based on the latest update from the "Galactic Warfare" Mod DB page, we'll likely see the public beta come out prior to Christmas.
Excuse me while I go take a breather.