[CentOS] Amazon AMI based on CentOS 5?

Hello,

Amazon has just released a custom Linux distribution (Amazon Linux
AMI) for use in their EC2 cloud:
http://aws.amazon.com/ec2/faqs/#What_is_the_Amazon_Linux_AMI

Out of curiosity, I googled a bit around it and read in various places
(e.g. [1] and [2]) that it is based on CentOS 5 (basically a stripped
down version) and should be compatible with most packages.

Do any of you have confirmation of this?
And more details/experience?
(I'm not a EC2 user, so I cannot check by myself...)

Thanks,

Mathieu

[1] http://www.cloudave.com/4872/open-source-and-cloud-computing-the-amazon-linux-ami-is-now-available/
[2] http://news.ycombinator.com/item?id=1693055