With the risk of being "killed" in the forum, another thing you can also try is Hydrogen Peroxide. You need to get food grade HP, and 35% strength, and you can do this directly in the tank. This is what I did on recommendation after I got Ich in my DT, and had no QT or any chance of getting all my fish out (unless I ripped my whole tank apart). You can read some of what I did in my tank thread.
What has been suggested above with a proper QT, copper treatment, and fallow tank is of course by far the best and the proper treatment, but the HP worked really well for me when I didn't have that option.
Let me know if you want to know more. Best of luck mate, Ich is not fun.....