Heropsychodreamer brings up a good point:

You will not be prepared for a skid until after you have been in one.

Most folks who have been driving for a few years will panic when they are in a skid (from some statistics given in my Driving Education class in High School). They will either hit the brakes as hard as they can, or they will steer in the direction they want to go rather than into the skid.

If the nose of your car starts pointing to the left, turn your wheel slowly clockwise until you feel the front wheels start to get some traction. Then slowly straighten your car by steering counter-clockwise until your vehicle is straight. For example:

1. Car is in skid. All motion is toward the top 
of your monitor.

             ___             ___
   F    -----___-------------___-----
   R    |                           |
   O    |                           |
   N    |                           |
   T    |    ___             ___    |
          Car is sliding sideways.

2. Slowly turn your car's wheels into the skid.

             /\              ___
   F    -----\ \-------------___-----
   R    |     \/                    |
   O    |                           |
   N    |                           |
   T    |    /\              ___    |
        -----\ \-------------___-----
          You will feel the front wheels start to
          rotate and grip. 

3. Slowly straighten your car until it is pointing 
the direction you are travelling.

We practiced skid control techniques in the parking lot of a large department store. I suggest you do this at night and in areas where there are no light posts or other cars. Make sure that the ground is iced and very slippery. Try to avoid going over 10MPH with a truck or Sport Utility Vehicle, as they tend to roll over during side skids. I-25 in Colorado (north of Denver) is littered every winter with the carcasses of SUV's that rolled over in skids. SUV's are not cars and they have a high center of gravity.

Get your car up to 10MPH. Turn the wheel quickly counter-clockwise, then hit the brakes until your vehicle starts skidding. Now practice the skid correction technique. When you are feeling confident, work on the other direction (steer right instead of left).

When you actually get some experience with skids, you will know how to react and how your car reacts. Skids take up a lot of space, and if you do not have space between you and what you're heading towards, all the experience in the world will not overcome the laws of physics. When the weather is bad, drive like you're 95 years old (except make sure your turn signals are off). I have already warned my daughter that she will learn these techniques when I teach her to drive. These techniques saved my ass and my car three times, including once on a highway in San Diego in heavy traffic and once on a mountain road with a rock wall on one side and canyon on the other.