To get things started on OpenStack, I am embedding a video by Rob Hirschfeld from Dell who does a nice job explaining OpenStack from a non-technical viewpoint:
As for the general overview, OpenStack was started by Rackspace, NASA, and about 20 other companies including Dell to create an open source alternative to Amazon and other proprietary public cloud vendors. There was no credible open source alternative available at the time thus the incredible growth seen in companies flocking to the OpenStack project. As of today, there are 144 companies who have partnered with the community and the latest code release, code-named Diablo, was shipped on September 22, 2011.
The project consists of a series of independent projects that customers can select from to create a custom cloud based on their needs. The projects are:
Two more projects will become core for OpenStack in the next release:
There are a host of other projects that are in development within the OpenStack community that may or may not become core. The complete list is at http://openstack.org/projects/.
As I mentioned earlier, Dell is a founding member of OpenStack and is playing a large role in the promotion of the solution to customers as well as driving the global message about the project. The Dell OpenStack-Powered Cloud Solution already has 13+ successful deployments and is busy driving new business opportunities. The DreamHost case study is a great example of how Dell is leveraging OpenStack to sell hardware, services, support, and software.