Thanks to malward, was trying this out yesterday. works pretty well for plain objects. but if you were trying to unwrap a face, or a section of a character than curves at the top and joins, say at the section at the top of the face, then you will have to change the area about a bit and give it more of a perpendicular edge. it works quite well actually :D
use spatial model aswell in the reactor cloth settings for fold stiffness.