LiEr from ikat bag shares a tutorial on her blog showing how to make a inside-out tiered pettiskirt. Most pettiskirts have a tulle layer underneath to make the skirt all cute and poofy. Her version is made cute by having the poofy tulle layer on the outside. (Actually, she uses a fabric other than tulle, which she found to be too stiff for an outer fabric.) Get the tutorial.
[photo from ikat bag]