EC2 stands for "Elastic Compute Cloud" and is the core of Amazon's cloud-based services. Use the Amazon EC2 API to create, configure, and manage virtual servers in Amazon's cloud.
To use the Choreos in this bundle, you'll need an Amazon AWS Secret Key and an Amazon AWS Access Key, which are used to authenticate your account. If you already have an Amazon AWS account, you can find both keys by logging into the AWS Console and going to the Security Credentials area. If you don't have an Amazon account, you can sign up for one here.