Microsoft officially supports CentOS on Hyper-V now. This is great news because CentOS is the flavor of Linux i prefer to use. I will go back to running this instead of SUSE on Hyper-V. Here is a great blog post about installing the integration for CentOS running on Hyper-V: http://www.ms4u.info/2011/05/centos-added-as-supported-guest.html
Here is a link on Microsoft of support Linux flavors in Hyper-V (CentOS is not added to this list yet.):