I think everyone has mentioned these things, so I will just list them:

Go on day hikes in the woods. This means drive to trailhead, park, walk a distance, walk back to car, drive home, sleep in your bed at home. You can practice navigation skills and hiking technique (ie, rest step) etc.

Go on overnight trips. Start in backyard to get familiar with new gear purchases. Move to car camping, and then to overnight backpacking.

Look at a hiking group like on yahoo or something. They will have beginner trips with experienced people who can individually teach you skills that you won't even know you needed to know.

There really isn't a lot of skill in backpacking. It is pretty much walking with a pack on. Sure, there is skill in making it more comfortable and safer, but just doing it will help you there.