WordPress MU

HI, where i can get the stable version of wpmu? i download the wpmu from its website, but it can not create a subdomain, it did not works well.
i like http://wugga.com/ this one very well, could you anyone let me know how to set up a blog like this one?
Thanks
Mike

For your nightly go to...
http://wpmudevorg.wordpress.com/nightly-builds.php

There's a thread on wugga's site. Search it. :)