I actuallly posted a similar question a couple months back. The recommended brands were Ben Nye and Kryalon. Sealant will probably be both of our saviors when it comes to keeping the makeup from peeling or rubbing off on to our clothes.
I've yet to get a good recommendation where to buy Ben Nye, but Kryalon can be bought at a store called "Hollywood Lights" in Portland from what Malaria told me.
I've never tried either brand, but I've heard of both of them, whatever that's worth. I might go with Kryalon just because I don't have to use the internet to get it.