One more thing to all Mac users:
If you use mac you can get a great program called 'KisMac' which is a great network sniffer / network probe / WEP password cracker / server crasher.
I used it once to hack into our schools proxy network, and steal the internet on my laptop lol. ANd you can flood an IP with hundreds of thousands of completely random packets of info each second which can crash a server in a couple of mins
Did that to my school network after my ICT teacher pissed me off. It's pretty easy, you basically do it in the stage where you're trying to get the SSID of the network hub, you change the incoming / outgoing packet rate and hey presto, one fucked server.