iPhone Connected To Wifi But Remains On 3G

[3gsowner]

I own a 32GB 3GS and it's started having a strange problem with the Wifi. Whenever I turn it on it manages to connect to my router with full signal strength however the icon in the status bar does not change to reflect a wifi connection it instead stays on '3G'.

I've tried updating the firmware to 3.0.1 and it hasn't fixed it, I've also tried to forget the network and reconnect. It just will not seem to use the Wifi connection.

Any suggestions?

Thanks.

 

[Planky]

I get this problem with all other WiFi networks except the one at home.
You could try resetting your network settings.

Settings -> General -> Reset -> Reset Network Settings

Sometimes I have luck by turning on Airplane mode then turning on the WiFi.
When I am having this problem I go to Settings -> Wi-Fi then click on the blue circle thing next to the network I am connected to and invariably only the first two fields are filled in "IP Address" and "Subnet Mask", the rest are empty. You could try setting the iP Address tab to static and fill in the fields yourself.