You can only download it off Battle net if you opted in and got it. You can also download it off pirating websites but no beta code which you need to log in.
get a baby, take it by the head and do a javelin throw to the computer and a pop up will come up saying the following....if the baby inst dead pick the bloody baby up and repeatedly slam the head on...
When opening StarCraft 2, the client automatically checks for patches and updates accordingly. If the game runs without updating, then you are up to date!