Cooperative Linux is the first working free and open source method for optimally running Linux on Microsoft Windows natively. More generally, Cooperative Linux (short-named coLinux) is a port of the Linux kernel that allows it to run cooperatively alongside another operating system on a single machine. For instance, it allows one to freely run Linux on Windows 2000/XP, without using a commercial PC virtualization software such as VMware, in a way which is much more optimal than using any general purpose PC virtualization software.

New releases hosted @ SourceForge:
Images 2.6.x Fedora - Fedora 10 - February 28, 2009
Images 2.6.x ArchLinux - ArchLinux 2007.08-2 - February 7, 2008

http://sourceforge.net/project/showfiles.php?group_id=98788