I am wondering if you mean the boost pressure from a turbo? This is not vacuum, it is pressure. Merely find a location between the turbo and the intake, drill and tap to mount a line, making sure to clean any drillings from the intake of the engine.
Lots of people actually tap into the cool side on the turbo. Right on the out part of the cool side. But I have heard many people doing it from the brake booster line as well. My turbo eclipse is tapped into the intake pipe. It is really just preference.