The Dev Server is not open yet, but you can download most of it now to version 220.127.116.11
It is best to do it now rather than wait for it to open. It took me one hour on a 20mbps modem.
If you wait until it opens you will miss a lot of playing time.
If you update now, all you will need is a small patch when it opens and you are ready to rock n' roll.