Progressive muscular relaxation is a relaxation technique where you work through the body tensing and releasing muscles. Developed in the 1930's by an American doctor Edmund Jacobson, it has stood the test of time. It is a good technique to just generally help you relax. It can also be used with another technique called systematic desensitization eg for phobias.
This recording is about twenty minutes long. It is best done in a chair. Here is some further information including contra-indications
http://stresscourse.tripod.com/id41.htmlMMU Counselling, Health and Wellbeing Service