For the IT worker, the phrase "desktop mobility" has many meanings. It can mean having a laptop computer. It can mean keeping all your data in the cloud so that you can access it at any time and from anywhere. It can even mean downsizing your work environment to fit on a PDA or a smartphone.

In each of these cases, a common denominator still applies: the need to carry with you one or more devices with which to access your applications and data. However, with the emergence of virtualization technology, it is now possible to take your complete working environment with you -- including all of your applications and data -- on something as small as a USB stick.

The idea of a mobile virtual machine is not new. Both VMware and Microsoft (via its acquisition of Kidaro) have been promoting this model for some time. What's different today is that you can achieve many of the same goals -- machine independence, the ability to conduct business travel sans laptop -- without resorting to the often limiting confines of a VM.

Thanks to the magic of application virtualization, you can now place all of your key work-related programs and data onto a portable device and access them directly from any Windows-based desktop, with the full fidelity and performance of the local machine. It's the ideal solution for situations where a zero-footprint runtime scenario is required, such as using a kiosk PC in a hotel lobby or working at a locked-down desktop in a secure environment.

Of course, to create virtualized applications, you need an application virtualization solution. For the enterprise, that means either Microsoft Application Virtualization (formerly SoftGrid), Symantec SVS Pro (formerly Altiris), or VMware ThinApp (formerly Thinstall). Microsoft's solution is free to Microsoft Software Assurance Program customers. Even better, Symantec SVS is free for personal use. Unfortunately, the solution best suited for extreme mobility scenarios, ThinApp, is the most difficult to come by -- at a starting price of US$6,050 for 50 client licenses.

In this article, I'll show you how to build a fully functional, virtualized environment that runs from a USB key or portable hard disk, requires no software installation of any kind on the hosting client PC, and leaves no trace once you've disconnected your media. When you consider the possibilities for true device independence, not to mention the obvious advantages during a disaster-recovery scenario, I think you'll agree that application virtualization can and should be a key factor in any enterprise's long-term mobile computing strategy.