How do I activate a new Boost Mobile sim on unlocked iphone 3GS?

I have unlocked iphone 3Gs and I want to replace my AT&T Sim Card with Boost mobile sim. I bought a brand new boost mobile sim and want to activate it and be able to use it on my iphone so how do i do that

Its very easy process to unlock it but in my view you need to visit a mobile center so that an experienced person will unlock it! Because any problem in unlocking will lock your iphone permanently! and it will charge hardly 500rs.. and when you will unlock your iphone you will make it stylish and beautiful by covering it with stylish skins from http://www.decalskin.com/ ..

Free t-mobile sim unlock code