Brent,
When shooting the milky way I had my aperture wide open--as wide as the lens could go--and set the exposure time to 30 seconds. As well as setting my shutter to that speed, I was also shooting anywhere from 2400-3200 ISO. Once you've got that setup, you then just need to make sure your lens is set to manual focus and that the focus is set to infinite.
While setting up the station I also checked a few things; like where the best shots of the milky way would appear, and what foreground would look best. Its easier to do this by taking some sample shots at a much higher ISO, just to see where things line up.
Just know while doing these shots it also mattered what time it was. I took these between 11:00PM - 2:00AM. Anytime before that and you'll get too much light pollution in the frame. Anytime after that and the 'prime' area of the milky way seems to disappear over the horizon. (Lets just say I had a few sleepless--cold nights, as I took these shots no where near I was camped to avoid any kind of light pollution from our tents/flashlights, etc.
I'm planning on doing a similar trip in Yosemite soon, but after this one I'm gonna take a break for a while.
