The outer part of the heel will make the initial contact with the ground. To have complete contact with the ground, the foot will roll inward about 15%. This slight inward motion can support your own body weight with no problems. The rolling in the foot allows the shock to be absorbed evenly. As the stride cycle ends, the runner will push off evenly from the front of the foot. Runners with normal arches usually are considered to be a normal pronator.
The best shoe type will be:
Neutral: Provides extra shock absorption in midfoot area.
Minimalist: As close as you can get to barefoot running. Ideal for "natural running."