Non-compete agreements, in which employees agree not to go to work for a company's competitors, are becoming increasingly common for lower-ranking employees. Companies use these agreements to protect valuable confidential information. There is no standard non-compete contract because laws vary from state to state which has led to a number of these agreements being challenged in the courts.
See "As non-compete agreements spread, resistance builds", Ameet Sachdev, Chicago Tribune, July 25, 2004