Today my friend told me about checking others balance from my phone. So i taught to post this tricks for my fella readers. Impress your friends with this trick....
 

How to check friends mobile balance in Docomo?
Dial 09045012345 Select language by pressing 1 Or 2
Then, Select 1
Type < your friends 10 digit tata docomo no >
Then Select 1.





How to check friends mobile balance in LOOP?
Dial 09821099500
Enter 91 followed < your friends 10 digit Looop no >
She will let you know the balance and you can even recharge through a Recharge voucher





 How to check friends mobile balance in Airtel?

Actually this works only for tamil nadu. Try this in your state and share your result.
Dial 12140 from your Airtel mobile number. When the call get connected, Select your language( if you haven ’t changed it). 
After the IVR language is selected then Press 2. Now enter your your friend ’s mobile number without any “0″ or +91 at the beginning of the number (enter only 10 digit mobile number). The system replies the mobile number which you entered. Just confirm it by Pressing 1 It will surely ask for the PIN of entered mobile
number. Enter the PIN as 1234. This step is more important. If you finished all the above steps now finally Press 3 to find the balance of any Airtel number.
Working in some states....