If you were interested in purchasing StarCraft II digitally we have some good news for you, Blizzard has added a download link for the StraCraft II game client, which is live now.
If you want to buy StrarCraft II digitally check out the Battle.net website, here you can log in with, or create a Battle.net account. Once logged in got to services and click “Buy StarCraft II Digitally”.
Once downloaded you will have to wait until the official release/launch date to play the game, but it is at least easier than heading down to your local retailer.
From what we can see the install is coded in way that stops you from installing it before the game’s release/launch date (July 27th), so to be honest I would consider waiting until perhaps July 26th as Blizzard may release a few bug fixes and patches over the next week or so.