This portfolio folder which was released only at 2009's San Diego Comic-Con, contains the FOUR images you see below in a very nice 10 x 15 in. (25.5 x 38 cm) litho format which really brings out the color and the little nuances of Alex Ross' art. The first three images were covers for The Village Voice, a NYC newspaper, while the last one was done to support Barack Obama in his presidential campaign.
If you want to learn more about the Village Voice images, please visit the newspapers section of this site.
(Above Left to Right: Uncle Sam - Truth, Justice and the Comics; Sucking Democracy Dry; Make Love, Not War - these were all covers for The Village Voice newspaper; Left: Super-Obama - created for Obama's campaign)
Where can you get these lithos? I got them from Spidey Collectibles/The Comic Newsstand on eBay. They sell these images individually (here are the links: Uncle Sam, G.W.Bush, Bush/Cheney and Obama) or you can contact them to get the full portfolio with all the four images at a discount. Trust me, I got a very fair price for this portfolio from them, they're really nice people and they love comics as much as I do.