The easiest way to make it is using the Rings that Bind pattern book by Cheryl Phillips. It takes a LOT more fabric to make it but it's faster, easier and no quilting when you get done. I made a pillow top to see how easy it was and it's EASY.
http://www.phillipsfiberart.com/
also Judy Martin has a Monet Wedding Ring pattern that is all straight edges. Super nice.
http://www.judymartin.com/Viewer-Photos.cfm
look under pictures from Sraps, Monet Wedding Ring