Kay Wood uses one of her rulers for this technique. I know there are several other rulers on the market, including Quilt in A Day but I haven't used them.
One what that is kind of cool is Ricky Tim's method of one seam flying geese. It makes a kind of three dimensional flying geese.
http://www.youtube.com/watch?v=78Mu0C_QL8Y
If I have a lot to make, sometimes I will be lazy and use the wondercut ruler to make hst and sew two together to make the flying geese.