I'm currently testing Ubuntu as a cloud client ...
For my test I had to use Hyper-V as an host hypervisor.
I noticed that even if the virtual machine "addition" (understand "drivers") are built-tin in the distribution 10.4, they are not active by default.
Read more if you want to know how to proceed to have a full Ubuntu 10.4 under Hyper-V R2
1/ First create a standard "Guest" ie: 5Gb of HD, 1Go of RAM
2/ Attach a CDROM ISO with the Ubuntu 10.4 distribution
3/ Boot on the CD, proceed with the installation.
4/ After your first boot, launch the console (ie ALT-F2 and type gnome-terminal)
5/ at the prompt type sudo gedit (don't forget "sudo" to avoid read-only mode)
6/ open the file "modules" under \etc\initramfs-tools\
7/ Add the following lines :
8/ Save the file modules
9/ exit gedit
10/ you are normally back to the prompt type, and type : sudo update-initramfs –u
You are done, with a nice Ubunto under Hyper-V.
* Don't make an "Ubuntu update", your installation will failed (at least at the present time 19/7/2010)
* I noticed that the mouse grabbing is not working in your Ubuntu session. This if you access your Hyper-V by RDP and from the Hyper-V mmc you connect to your Ubuntu.
As workaround you need to activate the Remote Desktop under Ubuntu and use VNC.