How To Convert -:
1. First Recharge with any Small 3G Pack
2. Then Share Data by Sending ADD(airtel mob no of your frnd with whom u r going to share ur data)
3. Then Recharge with Rs.8 Night Unlimited Pack by *129# (choose night Internet pack)
4. Every thing is done now
5. Just Keep your data ON and download small whatsapp pics videos (not that necessary if u don't have any media in ur whatsapp ) but better u download if u have
6. You will get 3g speed till 4 am...may be till 6 am. Enjoy