This site was made for simple purpose - explain to new or not enough experienced players how to play Starcraft Brood War online.
You just have to follow those few steps (and download required files):
Active international server with LAN latency, ladder, tournaments, replays and much more. Easier to go for newcomes.
Active Korean server with ladder. Occasionally you can meet non-korean there, but it's rare. The average skill level there is way higher than on ICCup.
You can join Fish by creating account in game, you don't need to register on web site.
You might have issues while trying to host the game. This is caused by automatic blocking of incoming connections and can be fixed with port-forwarding in your router settings. Generally, you need to allow port 6112 for the game. Each router has got a bit different settings interface, but this guide might help you.
You might encounter annoying graphic glitches while running Starcraft on these platforms. The solution to this problem is here.