I play Minecraft! I've been playing it a bit too much lately. A word of advice to other players; the Creepers are forming alliances. I had one cornered and it wasn't attacking me. Then I turned around to find 5 other creepers behind me, all blowing up at once.

With regard to the server, I'm fairly certain that you just need to download Minecraft_Server.exe from here, and run it. Then people just need to type in your IP to join.