The code consists of four drivers that are part of a technology called Linux Device Driver for Virtualization. The drivers, once added to the Linux kernel, will provide the hooks for any distribution of Linux to run on Windows Server 2008 and its Hyper-V hypervisor technology. Microsoft will provide ongoing maintenance of the code.
It's drivers. It's GPLv2. It's in the Linux kernel tree. And it's going to be actively maintained.
That's big. And brilliant.
Bad day for VMware. But a very good day for Windows and Linux users.