Amazon has a PlayStation Network store now, and it is exactly what you think it is. You can buy digital copies of games and downloadable content to play on your Sony gaming device.
Right now you can get a $5 credit if you buy a select title from the new store, so it might be worth checking out. Some games I saw are discounted a little bit too, which is always nice.
via destructoid http://www.destructoid.com/now-you-can-buy-psn-games-from-amazon-265504.phtml