How to change the iPhone Wi-Fi address on iOS 5?

I can't find a way to change the Wi-Fi address on my iPhone running iOS 5. I know it could be changed in previous versions with spoof programs from Cydia and others. I have tried the ifconfig string in mobile terminal but that does not work either. Anybody have some suggestions? This is really bugging me.

I Guess that you want to change the local ip-address that your iPhone has in the Wi-Fi or LAN.

You can do this very simply by going into Settings > Wi-Fi >
Take the blue "arrow" next to your Wi-Fi's name
>Click the Static (IP)
The meny should look like: DHCP | BootP | Static

In the Static page you fill out the informationen needed for your network.
Where you set the IP-address to the one you want to use.