Open source cloud virtual server software

I am looking for an open source virtual server cloud framework library. If there is anything like this, I plan to start my own sort of simple Amazon EC2-like service (I have the hardware, I need to make or obtain the software). I apologize if this is a ridiculous question, but if it is, please point me in the right direction.

Thank you, I appreciate your time.

From serverfault $pageUsers[$entry.posts[0].author].name

• I remember that Ubuntu has something called Eucalyptus : http://www.ubuntu.com/cloud

  From Peter Tillemans

• Sounds like you are talking about virtualization. Look in to Xen. There are a few vps hosting places that use it. I have a vps on xen hvm and have had a great experience so far.

  From $pageUsers[$post.author].name