Microsoft's Surface tablet is based on the ARM processor and runs the lightweight version of the new OS, called Windows RT. The $499 tablet has a keyboard and ships with Microsoft Office.
It can also run apps from the Windows Store marketplace. But it is not sold as an enterprise product: there is no support for the Microsoft Active Directory or x86-based Windows applications and Microsoft has not announced enterprise licensing.
However, businesses can "side-load" enterprise applications and use web-based apps, on the built-in IE10 browser.