Here Are Some Tricks to unblock ur blocked Airtel sim:-

=> Method 1 :-
Just Send MSG For Porting.In
Back Call Says I purchased an
Airtel SIM for Free FACEBOOK
Many User’s Using Airtel FREE
FACEBOOK in Mobile and PC

But in my Sim Not Facilities Available Right Now So I am
porting. After 2 -3 hours your
SIM Automatically Activate.

=> Method 2 :-
First you deactivate your
Airtel 3G or Any GPRS
Randomly.Then Remove
them for 4 Days and keep
your Sim in safe Area. Now
Use Another Sim On your mobile (This is the Main
Tweaks). Now Insert your Old
one Sim After 4 Days. And
Now Again your Sim
Activated. This method Safe
and Secure.

=> Method 3 :-
Best Method Forever.Create
MSG “FACEBOOK” and Send to
54321.Send MSG above
Continuously At
least 10 Times.Now after this
work restart your Phone and Get Successfully Active SIM
Unblocked.

=> Method 4 :-
First your Remove SIM from
your Mobile And.Again Put
SIM in GPRS Unable Handset
Phone Like 1100, 1110,Nokia
1600.Now Send MSG “MO” to
54321. Remove and Put SIM in GPRS Enable Mobile Phone (in
thisRequired Time minimum
5 minutes between Remove
and Put SIM in GPRS Enable
Handset). all do