Now you can check your girlfrnd's or anyone's mobile balance in airtel.
All you have to do is follow these simple steps:

Dial 12140 from your mobile and select your language. 
After that you press 2 and type your buddy's mobile no.
Type 1234 as pin code and then press 3 to know the balance.
If you like this post please do comment.

go to  http://dnd.megarush.net/balance-check.php to check for Reliance, Docomo and DND registration.