More than half of IT organizations are using virtualization technologies, according to a vendor-sponsored survey.

Rackspace sponsored a study of 245 customers of its managed hosting business and found that 57% of their internal infrastructures were virtualized. Of those surveyed, 72% said they would host business-critical applications on virtual machines.

In the "of-course you would say that" category, 71% of the respondents said they would prefer to host those mission-critical applications on a virtualized platform provided by a managed hosting provider such as RackSpace. Not surprisingly, of those respondents who had not used virtualization yet, 64% said they would like to try it with assistance of a hosting provider.

The survey pointed up some surprising results, too. More than 50% of respondents said they wouldn’t want to share a virtualized physical server with other hosting customers, citing performance and security for their reluctance to share a virtualized environment. Only 13% of the respondents said they would have no hesitation sharing a virtualized environment with other customers.

The survey showed not surprisingly that 60% of respondents use VMware, 14% use Microsoft Virtual Server and 11% use the open source Xen hypervisor or the commercially available Xen Enterprise to virtualize their environments.

The highest use of virtualization is for testing and development (37%), followed by Web serving applications at 22% and application servers at 12%.

Rackspace expects to offer virtualization services for its customers that draw off the survey results -- the offering is presently in beta test.