Windows Server 2008 Hyper-V Insiders Guide to Microsoft's Hypervisor
Although not published yet, this book is written by 3 senior Microsoft Hyper-V PMs (John Kelbley, Mike Sterling and Allen Stewart). For more information take a look at http://eu.wiley.com/WileyCDA/WileyTitle/productCd-0470440961.html
Patrick Lownds