How To Unlock iPhone 4 iOS 4.3.5/4.3.4/4.3.3/4.3.2/4.3.1 – 4.0 4.10.01/3.10.01/2.10.04 – Gevey Pro

I want to buy an iPhone 4S but they are out of stock at the moment in meteor and o2. I was looking on the apple website and i noticed you can buy iPhones from their website but they dont say anything about your phone providers. I am just worried if i buy the iPhone off the apple website that it wont accept my meteor or o2 sim card.