FYI, this is a solid build. I have been running RC1 a few weeks and many of the annoying little quirks of the earlier versions are gone.
Grab a copy of Hyper-V RC1 for Windows 2008 x64
here.
To use the remote management on your Windows 2008 x64 Hyper-V RC1 server, install this update
here.
Grab a copy of the management tools for Windows 2008 x86
here.
If you need the management console for non-Hyper-V systems, like Vista, you can grab those tools
here.
Hopefully this isn't all too confusing - most people will only need the first update listed. The rest deal primarily with remote management.