Blizzard is pulling the demo for Starcraft II and replacing it with what they're calling the "Starter Edition", which is essentially a bigger more badass demo/preview of the full game. It will feature more levels of the single player game as well as access to custom games against the AI (playing as Terran only). Still a demo to be sure, but a much larger one that will sell new players on the game a little more than the tutorial levels the original demo had. The Starter Edition will feature

• The first four missions of the single player campaign
• The first two challenges
• Play as the Terran race in custom games and single player vs AI
• Access to four custom maps, which may rotate over time: Xel'Naga Caverns, Shattered Temple, Discord IV and High Orbit