Free and available under the GPL version 2 or later, openQA can test any OS capable of running on a virtual machine. Although currently the web interface is only available for openSUSE, openQA is cross-platform capable. The OS-authoinst software supports Fedora, Ubuntu, Debian, FreeBSD, and OpenIndiana, and can also test MS DOS and Windows.
Check out demo videos to see openQA in action.