The steering wheel moving by itself is discussed in this thread http://www.chevymalibuforum.com/forums/showthread.php?t=2666. It looks like you need to get your electric power steering (EPS) looked at. It's usually the EPS motor/module assembly, not a usual DIY item. Go to http://www.aa1car.com/library/steering_power_electric.htm if you'd like to know how these things work.