Slicing the ball is never fun. A great drill to combat the slice is to swing the club using only your right hand with light grip pressure. The goal is to feel the right hand rolling the clubface closed through the hitting zone. Because of the lighter grip and no left hand in the way, you'll quickly feel an exaggerated roll of the hands through the shot. Try it, then make a few normal swings, and remember that the left hand is just along for the ride.
Justin Klemballa, PGA, teaches at the Jim McLean Golf School at Sunridge Canyon GC in Fountain Hills, Arizona. You can get more information at sunridgecanyongolf.com.