Eucalyptus – Elastic Utility Computing Architecture for Linking Your Programs To Useful Systems – is an open-source software infrastructure for implementing “cloud computing” on clusters. The current interface to Eucalyptus is compatible with Amazon’s EC2, S3, and EBS interfaces, but the infrastructure is designed to support multiple client-side interfaces. Eucalyptus is implemented using commonly available Linux tools and basic Web-service technologies making it easy to install and maintain.
From the docs I’d guess Eucalyptus is not the typical five-minute-install and I’m not sure yet about the supported plattforms. Since there’s a lot of mentioning og RPMs in there I guess I better start with some Linux boxes to give it a try.