Microsoft's VMware Attack [forbes.com]

Microsoft Thursday started selling Hyper-V, a so-called "hypervisor" or platform that lets computer servers run many applications and operating systems at once. This means companies can use fewer servers for their data-processing needs, thus reducing energy costs.

Hyper-V, which has been in beta since February, comes free with a copy of Windows Server 2008. Separately, Hyper-V sells for $28. "The price is right," says Rob Helm, research director at Directions on Microsoft. "People are going to take it as a serious alternative" to VMware's much-pricier hypervisor.