Giny's right about not buying any "Vick Endorsed" products.
You can take it further by watching the Falcon games and making a note of who advertises on the telecasts.
Then write each sponsor letting them know that not only will you not ever again buy another one of their products, but as long as they sponsor Falcon games on TV you will make it a point to buy from their direct competitors.
Say Budweiser buys ad time on a Falcon telecast. Write Budweiser and tell them that you're through buying Bud, and from now on you're drinking Miller. Let them know it's because they support a team who supports Michael Vick.
It doesn't have to be true. Maybe you don't drink beer. But a little BS could go a long way.
If you're watching a Falcon game and see a commercial for Dodge Trucks, write Dodge a letter. Let them know you were going to buy a Dodge Truck, but because they support the Falcons, and the Falcons support Vick, you're going to buy a Chevrolet Truck instead.
Enough people mess with their money, or give the appearance their money's being messed with, and you will see results.