If you need on demand computational power, and at massive scale, then Ryan Waite shows you how with HPC Pack 2008 R2 in this video:
http://blogs.msdn.com/b/windowsazure/archive/2010/09/20/showcasing-high-performance-computing-on-windows-azure.aspx
After creating a node template (standard for HPC machine types) of type Windows Azure you can:
There is a great disco heat map of the cluster over the HPC Server Nodes (On Premise and Off)