On your HTC Desire S you can control settings for Wifi and Networks.

Once you have entered the Wireless & networks menu you are able to change the following

Airplane mode – Wi-Fi – Wi-Fi settings – Bluetooth – Portable Wi-Fi hotspot – VPN settings – Mobile networks and USB tethering settings.

To enter these settings follow these steps

Press the Menu Button – Press Settings – Press Wireless & networks – then just follow the prompts.

I know this post seems a bit simple but it is meant for new users.