Five minute exposure... tripod (guess that's obvious!); remote shutter release; iso on 200. Guess that's it. My wife took the photo while I grabbed the flashlight and shined it on the Jeep's windshield (5-10 seconds on each side) to get this effect. This photo was taken toward's the east, with Copper Mountain College and the town of Joshua Tree being the dominant lights.
The photo below was a 10 minute exposure, facing south towards Joshua Tree National Park. Not sure I'm totally pleased with the photo, as it has kind of a blurry look to it. But kind of cool that you can see the movement of the stars over the long exposure... the dots become lines! The wispy looking cloud is the tail end of the Milky Way.