Okay, I don't know if this is a stupid question (I always say there's no stupid qusetions, only stupid people;P) but can I ice angel food cake with buttercream? I know that before it bakes it has to be free of fat but after? Not so sure....If not, any suggestions for covering? - It's for the top tier of a wedding cake....

Not stupid at all! Ice away! Once it's been baked, you can top angel food cake with whatever you want. The 'no fat' rule only applies to the pre-bake mixing.
Although, buttercream does defeat the purpose of a 'fat free' cake !