Do you know you can share one internet connection with other devices which can connect to WiFi? I recently learnt a great stuff from a friend and want to share with you. Well, we going to do this on Ubuntu. Assuming you use a USB modem like I do OR You go to an internet cafe you can just create this hotspot and use your cell phone with it. Then this can help you.
1. Go to System Settings.
2. Select Network.
3. Select Wireless.
4. Below the Networking window (as shown below) Select Use As Hotspot.
You can also choose your own Wifi-Password by visiting the WiFi Setting also from the Network window from the System Settings.