From the CentOS Announce mailing list, we now have public CentOS 6 images in Amazon!
CentOS-6 x86_64 with updates : https://aws.amazon.com/marketplace/pp/B00A6KUVBW
CentOS-6 i386 with updates : https://aws.amazon.com/marketplace/pp/B00A6KZBC6
CentOS-6.3 x86_64 without updates : https://aws.amazon.com/marketplace/pp/B00A6L6F9I
CentOS-6.3 i386 without updates : https://aws.amazon.com/marketplace/pp/B00A6L0O04
Nice job CentOS Team!