Spurred by the business benefits gained from server virtualization, enterprises now are embracing desktop virtualization for many of the same reasons: flexibility, lower costs and ease of management.

The latter has been huge for the University of Maryland in College Park, says Jim Maloney, network applications manager at the school, which has been using desktop virtualization since November 2007. The university hosts 50 -- soon to be 250 -- virtual PC images on two VMware ESX servers running the Sun Ray Server Software and Sun's virtual desktop software. Users access the images from Sun Ray terminals. "Overall, we've saved 30 hours a week in management time -- practically one full-time employee," he says.

Others look to desktop virtualization as a hedge against the cost of future PC upgrades. "Compared with traditional desktops, virtualization is a no-brainer," says Kunal Patel, IT manager at Nina Plastics, a packaging manufacturer in Orlando. Nina hosts 50 virtual PC images on two ESX servers using Pano Logic's Virtual Desktop Solution software. Users access the hosted images from a specialized hardware-only device into which they plug their mice, keyboards, displays and network connections.

"We were spending between $700 and $1,000 per desktop, whereas the Pano device costs just $300. And an actual PC eventually becomes obsolete and has to be replaced. With the Pano, if we want to upgrade the entire company's desktops, we just upgrade the few servers we have and we allot more memory or faster speeds to the images. It's a concrete dollar savings," Patel says.

Plus, users get unprecedented flexibility: They can access their desktops from virtually any device residing anywhere, as long as they have good network connections. Instead of sharing centrally hosted applications, they access their full desktop images complete with familiar applications and customized wallpaper -- the final fulfillment of the thin-client ideal.

One, two, three approaches

Desktop virtualization requires a hypervisor, such as VMware ESX, Citrix Systems XenServer or Microsoft Hyper-V, running on a data-center server to host the desktop images. Vendors differentiate themselves by the overlying desktop virtualization-management software that brokers the connection between the virtual PC image and the actual client, be that a Macintosh, Linux or Windows PC; thin client; RDP