Has anyone tried this method?

My brother gave me his old iphone4s from at&t and he said he would unlock it for me(so i could connect it with tmobile). Turns out he told his girlfriend to go unlock it while he was at work but she forgot to and then she forgot to tell him that she didn't unlock it.
i googled a way to unlock it myself for free but i just wanna know if anyones tried this and if its worked?

http://www.jailbreaknation.com/how-to-unlock-iphone-4s-no-jailbreak-gsm-only

That's a virus that seeps your information out. Such as credit cards, messages, calls, anything that they can use against you for a benefit of their self gain.