It is quite a good museum, situated in a hangar on the RAAF side of the airfield. It has a fairly comprehensive aircraft display. The centrepiece is the USAF B52 bomber, with the rest of the aircraft collection displayed around it. The display includes an F111, F/A 18, Mirage, and many more, including an old AH 1 Huey Cobra. With the hangar being quite full, they have a P3 Orion on the tarmac outside.
They also have a major theme around World War 2 and the bombing of Darwin with quite a few artefacts, along with smaller displays relating to Vietnam.
I have visited this museum quite a few times over the years, and would recommend it.