ISVs can now receive a special Hyper-V designation to support the Certified On or Works-With certifications for Windows Server 2008 applications. The designation lets those considering your software that it has passed compliance testing for Windows Server 2008 Hyper-V.
Basically to receive the "Certified for" designation, an application needs to pass all the test cases in a Windows Server 2008 virtual machine on a Windows Server 2008 Hyper-V.

Full story: dabcc.com