One of the first steps you’ll need to handle is surveying yoru current environment for good/bad virtualization candidates. Even though Hyper-V is not yet released, the tools below will help you get started on this key deployment planning task.

The Microsoft Assessment and Planning Solution Accelerator (MAP) scans the environment of servers, captures perfmon counters and recommends virtualization candidates.

The Infrastructure Planning and Design Solution Accelerator (IPD) guides offer tech guidance on what key decisions to make when designing a solid virtualized infrastructure.

Here is a blog post that explains “How-to do Virtualization Candidate Reporting.” And a MAP Video Demo. 
After you have your list, you’ll begint to plan migration of various workloads to virtualization. You’ll want to keep the support policy in mind:

897615  Support policy for Microsoft software running in non-Microsoft hardware virtualization software

Hardware virtualization software lets you run multiple operating system instances at the same time on a single computer. Microsoft has two software offerings, Microsoft Virtual PC and Microsoft Virtual Server, that provide this functionality. Third parties also have software in the market that provides this functionality. This article describes support provided by Microsoft for its software running together with non-Microsoft hardware virtualization software.

Except as described in this article, Microsoft does not test or support Microsoft software running together with non-Microsoft hardware virtualization software. For Microsoft customers who do not have a Premier-level support agreement, Microsoft will require that the issue to be reproduced independently from the non-Microsoft hardware virtualization software. Where the issue is confirmed to be unrelated to the non-Microsoft hardware virtualization software, Microsoft will support its software in a manner that is consistent with support provided when that software is not running together with non-Microsoft hardware virtualization software.
For Microsoft Premier-level support customers running non-Microsoft hardware virtualization software from vendors with which Microsoft does not have an established support relationship that covers virtualization solutions, Microsoft will use commercially reasonable efforts to investigate potential issues with Microsoft software running together with non-Microsoft hardware virtualization software. As part of that investigation, Microsoft may require the issue to be reproduced independently from the non-Microsoft hardware virtualization software. Where issues are confirmed to be unrelated to the non-Microsoft hardware virtualization software, Microsoft will support its software in a manner that is consistent with support provided when that software is not running together with non-Microsoft hardware virtualization software.
Microsoft will jointly support certain non-Microsoft hardware virtualization software from vendors with which Microsoft has established a support relationship that covers virtualization solutions. This joint support will include coordinating with the vendor to investigate support issues. As part of the investigation, Microsoft may require the issue to be reproduced independently from the non-Microsoft hardware virtualization software. Where issues are confirmed to be unrelated to the non-Microsoft hardware virtualization software, Microsoft will support its software in a manner that is consistent with support provided when that software is not running together with non-Microsoft hardware virtualization software.