How to Get WiFi to Work on My iPhone

The iPhone is an Internet, audio and video-equipped smartphone designed and manufactured by Apple. All models of the iPhone feature built-in Wi-Fi connectivity, meeting the 802.11 B/G compliance standards. Wi-Fi drains the iPhone battery even when it's not connected to the Internet, as it continually scans for new networks. Because of this, WI-Fi is sometimes turned off. Turning Wi-Fi back on, scanning for networks and connecting to the Internet can all be performed through the iPhone Settings application.

...
The 2.4 GHz iPhone 4 also includes 802.11 N Wi-Fi connectivity.

Step

Tap the "Settings" icon on the iPhone home screen to launch the application.

Step

Tap the "Wi-Fi" menu and slide the "Wi-Fi" switch to "ON." The iPhone will automatically begin scanning for Wi-Fi networks within range.

Step

Tap the entry for the Wi-Fi network you want to connect to in the "Choose a Network..." box.

Step

Enter the Wi-Fi network's passkey if requested, and then tap the "Connect" button. To acquire the passkey, check with the owner or administrator of the Wi-Fi network.