When on the elliptical machine my feet tend to go numb but somebody told me this is usual as your feet are not moving like when you run. However, I've been running 2 miles at a time now and my feet still go numb. Does anyone happen to know what might be causing this and / or what I can do to prevent it?

Sounds like a hardware issue: as in your shoes? Just a guess. I would either loosen up, not tie so tight, or maybe invest in a new pair of shoes. Find a specialty running store in your area and have an in-store expert evaluate your feet. You may over-pronate, have a high arch, or God forbid, you may do both! Nothing a slide in orthodic can't fix. Bring your running shoes with you when you go. They will look at your soles to see where they are worn on the bottom. You might just simply be wearing the wrong size. Running shoes are a different breed of shoe. For example, I wear size 8 women's shoe but in Asics, I wear a 9 or 9.5. Amazing, no? This is where I would begin. Then if things are not resolved I would consider checking with a podiatrist (one that is a runner would be your best bet)

Good luck!