I own and iPhone 4s and just recently updated it to the iOS 6. When I go Wi-Fi settings I press my Wi-Fi of choice, and it connects to it; for like two seconds, and then it defaults back to my 4G. I know my router is completely fine because I have reset that, and my laptop is running off of it now completely fine. I have already tried the "forget network" method. And the Settings-> General-> Reset->Reset Network Settings method. Neither of which worked.
Does it have anything to do with my update?