Dell has a blog post on its Cloud Computing Blog.

Dell Powers Microsoft Azure

Mon. Oct. 27, 2008

Today marks the start of an important chapter in the unfolding story of cloud computing. Microsoft has entered the ranks of cloud platform service providers with the launch of Windows® Azure™ and the Azure Services Platform. Microsoft selected cloud-optimized Dell servers to power the Azure platform.

Forrest Norrod, Vice President and General Manager of Dell's Data Center Solutions Division, took a moment to share his thoughts about the announcement in this video:

Here is the Dell HW used in ask.com /2008/05/more-details-on.html