Preparation: Experience

I see Philip's already covered the basics of gear to get when you start riding. So now I'm going to cover one point I've alluded to a couple times, but never really gone over in detail. This one is about building up experience. I wouldn't recommend going straight from an MSF class to riding 40 miles to work for a straight month. In the MSF class, you've been riding around in an empty parking lot in broad daylight, and usually in dry weather (although the classes are held rain or shine). On your commute, you'll have to deal with darkness, bad weather, bad drivers, and more.

So after the class, you'll want to build up experience. At first you'll want to just practice what you've done in the MSF class, either on side streets or parking lots. Then you can start adding more challenges - riding in somewhat heavier traffic, then maybe in the rain or night. Eventually you'll work your way up to longer rides, heavy traffic, the Interstate, and more. But don't bite off more of a challenge then you're comfortable with, and just try a little at a time - for example, you might want to make your first Interstate ride between two exits a few miles apart.

If you're wondering how much experience I have, it's about two years and 10,000 miles at this point.