The Azure™ Services Platform is designed to help developers quickly and easily create, deploy, manage, and distribute web services and applications on the Internet. Windows® Azure is a cloud services operating system that serves as the development, service hosting and service management environment for the Azure Services Platform. Windows Azure provides developers with on-demand compute and storage to host, scale, and manage web applications on the internet through Microsoft data centers.

Get the low down @ http://www.microsoft.com/azure/default.mspx