Recently, Everyday Health tackled the widespread problem of insomnia.

Amonng many great recommendations, they include a section on biofeedback to help combat a busy mind.

Relaxation techniques For some people with insomnia, a racing or worried mind is the enemy of sleep. In others, physical tension is to blame. Fortunately, there are ways to release physical tension and relax more effectively. Relaxation techniques that can quiet a racing mind include meditation, breathing exercises, and progressively tensing and relaxing your muscles starting with your feet and working your way up your body — a technique known as progressive muscle relaxation.

In biofeedback, people use equipment that monitors and makes them aware of involuntary body states (such as muscle tension or hand temperature). Immediate feedback helps people see how various thoughts or relaxation maneuvers affect tension, enabling them to learn how to gain voluntary control over the process. Biofeedback is usually done under professional supervision. Other relaxation techniques — such as progressive muscle relaxation or meditation — can be learned in behavior therapy sessions or from books, tapes, or classes.