4. Citrix: One of the oldest players in the virtual desktop market, Citrix, brings Windows to the iPad with its Citrix Receiver tools. These help IT departments manage users' personal devices (say in a company with a BYOD policy for mobile gadgets.) Centralized management tools let admins recognize Windows-on-iPad devices on a network and manage them alongside regular Windows PCs.

Citrix is selling Citrix Receiver as part of its XenDesktop VDI package or through its XenApp streaming software service. Citrix Receiver can be downloaded from Apple's App Store. It also supports Windows on Android.

5. Parallels: Parallels was one of the first vendors to offer a Windows on Mac solution, so it's not surprising that it was also among the first to introduce a Windows on iPad client. The Parallels Mobile App, available for $19.99 from the App Store, lets iPad users access Windows apps from any Mac that's running Windows through the Parallels Desktop client.

The app brings a host of new capabilities to the iPad, such as Flash and full access to Outlook and Explorer. It also supports cut-and-paste between mobile devices and Windows apps.

6. Molten Technologies: Upstart Molten Technologies [see video below] specializes in providing virtual desktop services for businesses. Its Desktone-based cloud platform streams what the company has coined "Desktop as a Service", and among those services is Windows for the iPad.

Its pitch for enterprise users is that all of its services are hosted at a secure, Tier 3 data center, and segregated networks are provisioned for each customer. Customers also maintain control of firewall and other security settings.

Microsoft and its partners are themselves expected to introduce a range of Windows 8 tablets later this year.

See the future of business technology at Interop Las Vegas, May 6-10. It's the best place to learn how cloud computing, mobile, video, virtualization, and other key technologies work together to drive business. Register today with priority code CPQCNL07 to get a free Expo Pass or to save 25% on Flex and Conference passes..