OpenStack is an Infrastructure as a Service offering. (see my prior post for an explanation of IaaS).
OpenStack is an OpenSource project, founded by RackSpace, NASA and others.
OpenStack can be deployed as a public or private cloud.
Project NOVA, or OpenStack Compute, provisions and manages on-demand virtual machines and associated resources: CPU, Memory, Disk and Network.
Virtual machines can be started, stopped, suspended, created and deleted, while network options for a virtual machine are static, DHCP, or IPv6.