Blizzard decided that Starcraft 2 will not have LAN support.
This decision is quite strange to me. Starcraft as a sport was raised on local network and low latency (just try to do Mutalisk micro on battle.net). I do not know what they did so great to their service too speed it up, but I am quite sure that it cannot be as fast as two computers next to each other. And that is even without thinking how speedy Internet play will be when Starcraft II comes out and all trillions of people try to play it at same time.
I do remember quite a few Starcraft games in hotels where ad-hoc wireless was all it was needed. Those days are gone now...