With this Tips you can check the mobile balance of your Friends in Airtel, Docomo, Idea and Bsnl .
Just Dial below Given Number for Checking you Friends Balance :

Airtel – 09810198101
Docomo – 09040012345 or 07737012345
Idea – 09824012345

Bsnl – 9415100123 (only for up) .

After Dialing Select language > Already Operator user > Enter Your Friends Number .

Done !
If in Airtel it will ask for Pin then use 1234 as Pin Number .

Note by sonukant.blogspot.in – Docomo Number is Toll Free but in other numbers Charges are apply as Std Call Rates .

This Trick is tested many times and 100 % Working .
Enjoy