Unfortunately, retail purchases don't include the ability to download before getting the box. I think after you register your key you'll be able to access the download, but not before.

::rubs his temples at the casual pirating suggestion above::

Ey-ya-ya...



Godowar,

Once you get it, you can install it from the disk to your harddrive. Then, if/when you get Stardock Central, you can input the registration code from the box. Then, input the serial number to connect it to your Stardock Central (SDC) account. At that point, it'll update. Also, at this point, you'll have made it so you can get the game at any time through SDC. Heck, the convience of SDC has made me consider buying a game I already own through SDC a second time.