This is something that both Paul and I want to research more but, there have been a lot of questions about this recently. So, I thought I'd pull together a quick post of some important resources if you're interested in virtualization.
1) You should know what the support implications are - Bob Ward (Microsoft PSS Principal Escalation Engineer extraordinaire) - has blogged about the support implications here: SQL Server Support in a Hardware Virtualization Environment
2) You should know some of the best practices in configuration and setup - and the SQL team (specifically the SQLCAT team) has just recently released a whitepaper: Running SQL Server 2008 in a Hyper-V Environment - Best Practices and Performance Recommendations.
3) Finally, here are a few additional - and helpful resources:
Have fun and post back with any issues on virtualization that you've run into!
kt