I don't think those are your normal button covers. I think they are done with the "button maker" New! 1" Button / Badge- Pin Maker Machine FREE SHIPPING - eBay (item 360154425485 end time May-18-09 14:53:17 PDT)
I'm sure it is the same thing as what everyone is talking about just with a different back. 500 - 1" Std Button Badge Parts for Maker Machine - eBay (item 200296166719 end time Jun-05-09 15:40:33 PDT)
This link here is for the buttons themselves, I wonder if you can use these without the button maker machine?