once you have downloaded this redsnow, install it on your pc and then also install Itunes. Now the next step is to simply make it inactive and then insert a new SIM with no PIN lock...now again make it active with the help of ITunes...enjoy your unlocked IPhone...

hi there......first your copy all you important pics from you iphone....now take a backup using ITunes....now delete all the settings and make it factory default....now you need to download redsn0w_win_0.9.15b3 and then follow the instructions