This has been discussed several times before. Here are some posts to get you started. It's sad that there are so many posts... so many in need of this therapeutic aid.
http://www.quiltingboard.com/main-f1...n-t209113.html
http://www.quiltingboard.com/main-f1...e-t186999.html
http://www.quiltingboard.com/main-f1...lt-t98568.html