Instead of using cellular data network on your mobile you can use WiFi network to enjoy much faster internet. You can connect to WiFi network available in your location or you can Share your Mac or PC internet with Windows Phone, see how to share Mac internet or PC internet with Windows Phone 7.
Tap the “Arrow” on home screen of Windows Phone 7 or Slide left.
Tap “Settings” and then “Wi-Fi“.
Here Make sure “Wi-Fi networking” is set to On. Tap the button to turn it On/Off.
Windows Phone will start searching and all available Wi-Fi networks will be listed below, tap one of them and connect to it (You may need to enter password if Wi-Fi is secured).
You can also check the “Notify me when new networks are found” check box here, so every time when Windows Phone will find Wi-Fi network it will notify you.
Disconnect from Wi-Fi network on Windows Phone 7
Tap and hold on a Wi-Fi network and tap Delete.