Bashiok posted:

If StarCraft II is any indicator you’ll be able to download the client beforehand, and the the installer will unlock at 10AM pacific time. So, if you want it right at midnight (or a collector’s edition), your best bet is probably a pre-order and midnight release at your local brick and mortar. But, this is all assuming things which we haven’t release any information about.

I’d wait for more info… like… a release date. ;)