As strange as this sounds.... I have found that if you go to settings and turn on Airplane mode and turn off Wi-Fi then go to /General/Network and turn off all of the settings: Enable3G/Data Roaming/Wifi ect. reboot your iPhone and turn Airplane settings back Off as well as turning your 3G and WI-FI back on to your original settings...I have seen the Wifi start working... It's more of a corrupt Preference Issue at times than a Hardware... it's a quickfix.. that can save you money...were all about saving money...