Ditto to what Sean said.
My local Lowes also has green foam board in 1" x 4' x 8' sheets. I find the 1" board a little easier to work with when cutting.
Other than the words "Lowes" versus "Owens Corning" being stamped on the foam and the color, from what I can tell the green board is the same as the pink board. I think the color pink must be copyrighted by Owens Corning :-)