Ok...so in the last 3 weeks I've been asked this numerous times (and to save emailing it again!), the article you need is http://support.microsoft.com/kb/888794/en-us. I guess just recently we've seen a step up in the workloads being virtualized and the increase in requests for workload specific guidance reflects this.
Microsoft has made changes to its licensing and support policies for Virtualization.
- Best Practices using SQL Server2008 and Hyper-V
- Support Policy Changes
- SQL Server 2005 Support for Hyper-V
- Licensing and Recent Changes
SQL Blog SQL Server Virtualization Blog