I was talking with my brother and sister this morning, and the topic of progressive muscle relaxation came up. It is based on early work by Edmund Jacobson, who first wrote about it in Progressive Relaxation in 1929, and the premise is that one can't simultaneously experience warm well-being and psychological stress. There are innumerable ways of accomplishing the relaxation response, and there are times when it helps to use the body and/or breath - when the mind is so uneasy that it can't be used to calm itself. Duh!
Anyway, you can find the instructions, including an audio-file here. I also recommend the book The Relaxation and Stress Reduction Workbook by Martha Davis, PhD, et. al. which includes information about PMR and a number of other related topics.