Where Can I Buy The Iphone 3g Charger That Originally Comes With The Iphone 3g

I bought an iPhone 3G and my dog chewed up the charger. I want to buy the original one that came with it because it is very small and easy to travel with. The only ones I can find are significantly bigger. I've tried AT&T stores and they do not have it. Can anyone provide a link or place where I can buy the original iPhone 3G charger?