Want to build a private cloud?

Want to build a private cloud?: "Creating an internal or private cloud that gives IT managers the benefits of a cloud running inside the data center isn't easy. IT pros will have to build it and glue it together themselves, as no single vendor currently provides all of the pieces needed. Some packaged software is beginning to appear to help create private clouds, such as Ubuntu Enterprise Cloud (UEC), but it's limited to Linux-based clouds."