Virtual Server 2005 R2 Support for WSS 3.0 and MOSS 2007
Although there was no support for virtual environments in SPS 2003 and WSS 2.0 in KB 909840. There is now product support for WSS 3.0 and MOSS 2007 with Microsoft Virtual Server 2005 R2 x86 or x64. Which you can currently download for free or order a CD. Although Virtual PC might be used by product support for reproducing issues, or in non production environments. There will be no support on Virtual PC. It is highly recommended to *NOT* run WSS 3.0 and MOSS 2007 production environments with Virtual PC.
Support for third party virtualization remains similar to how it has in the past. Please refer to KB 897615. It's possible that product support will require that you reproduce the issue in a non virtualized environment if they suspect that the virtual environment is a potential contributing factor in the issue.