This is the EASIEST video there is
Follow this:
http://www.youtube.com/watch?v=9LRSxQ7UoAc
(watch and follow tutorial from 1:25 till end)
just keep in mind that you have to type in wlan0 instead of mon0


But before you start video, you have to know this:
Load the driver first!
And when you start and everytime you run a new X Terminal, you need to be root

That's all !