- 1). Tap on "Settings," then on "Wi-Fi."
- 2). Locate the Wi-Fi network you wish to delete in the list of networks remembered by the iPod Touch.
- 3). Tap on the blue arrow next to the name of the network, then tap on "Forget this network." At that point, the iPod Touch will have lost all memory of having connected to that network -- and of its past configuration parameters.
Source...