May I suggest the sedona method (www.sedona.com) as an extreemely powerful tool for releasing any emotion. The basic method is on the website.
Also, in traditional chinese medical theory anger is stored in the liver and there is a taoist master who teaches breathing/ meditation techniques for clearing anger and negative emtotions from the body; two techniques given free on his website for this are the six healing sounds and the inner smile. (www.universaltao.com)