IMHO, one the of the coolest technologies to be released last year was Windows Server 2008 Hyper-V, the virtualisation just rocks, it's fast, solid and reliable. I run Windows Server Core 2008 (ie no GUI) so I manage the Hyper-V Role from Windows Vista Sp1 with Hyper-V Manager, so was a tad disappointed to find the Hyper-V management wouldn't install on Windows 7.
Anyways, fear no more, you can download the updated tools from http://www.microsoft.com/downloads/details.aspx?FamilyID=7d2f6ad7-656b-4313-a005-4e344e43997d&displaylang=en, once installed:-
The download link contains more information on setup.
Yes, you still need to enable the firewall and allow anonymous DCOM call backs if you manage a Hyper-V Server that is in it's own workgroup or domain. For more info on this then check out http://blogs.technet.com/jhoward/archive/2008/11/14/configure-hyper-v-remote-management-in-seconds.aspx