Changing out a faulty light switch or installing a new dimmer switch is something that even a newbie DIY enthusiast can take on. It doesn't require much more than some pliers, a screwdriver and a little help from Google. There are scores of step-by-step instructional sites on the Web that can walk you through this fairly basic process. The one thing you always need to remember is to turn off the breaker switch at the fuse box for the room you'll be working in. If you aren't too comfortable with your fuse box, just cut the main power for this quickie repair. But if your project entails more, like wiring for a new light, it's best to call an electrician.