Microsoft has all of this already in place, and millions of Windows and Web developers using Microsoft tools can start writing phone applications. In many cases, substantial of amount of existing code can be imported and re-used.

The latest versions of Microsoft's core developer tools all support Windows Phone development: Visual Studio 2010, Silverlight 4, Expression Blend 4 beta and XDNA Game Studio 4. All incorporate a Windows Phone emulator, running on a complete build of the Windows Phone 7 OS. Visual Studio programmers can drag and drop controls onto a Windows Phone surface, bring in existing Silverlight libraries or Azure cloud projects, and wire them up to data sources, behaviors and services, just like they do when writing software for a Windows PC.

It's a Microsoft-focused environment to be sure, but most enterprises have a strong Microsoft base with user PCs, Web infrastructure and back-end servers.

"Silverlight doesn't look like a problem," says Piers Finlayson, product manager (and former coder dealing with human interfaces) with , which uses, among other tools, Microsoft Visual Studio.

4. Windows Phone Marketplace tailored for enterprise