All you really need to do is walk. Walk around the neighborhood in the evening. Walk for 30 minutes at lunch. Park your car at the far end of the lot when you run errands, and walk to the store.

If you already go to a gym, then walking on a treadmill is easy. Keep the pace down to around 2 or 2.5 mph, and crank the angle up a little to start, and all the way once you've been doing it awhile. (If you can listen to music while doing this, it helps -- treadmills are hellishly boring.)

After a month or so of walking around the neighborhood, you should be able to walk for an hour or more. Now it's time to add a pack -- just a regular "bookbag" type backpack would be enough. Add some weight -- about 15 pounds is good -- and keep walking.

If you can hit a real trail at a local park on weekends, by all means do so. Bring your pack with some water and snacks or lunch, and enjoy the walk.

Being out of shape definitely slows you down, but it doesn't keep you from walking and hiking. And the nice thing is that the walking gets you into shape.

Happy trails.