StarCraft is on the PC. It's also on the Mac. And Nintendo 64. And that's it. So how is somebody playing the strategy hit on a touch-screen Apple iPad?
It's not through magic, nor is this a bootleg copy of the game. It's actually a program made by a company called iSwifter, who normally stream simple Flash games to handheld devices through the "cloud", but who in this case have made an exception and got a custom version of Starcraft running instead.
Some controls are accessed via the "buttons" along the side of the screen, while others are done by using more iPad-like gestures like pinching and dragging on the game screen itself.