1. AIRTEL
Type FREE and send it to 54321(tollfree) OR send a blank sms to 59103(tollfree), u will receive your mobile no. in a sms, Or dial *140*1600#, *400*2*1*10#, *121*9#
2. AIRCEL
On your aircel mobile dial *122*131# or *888#
3. TATA DOCOMO
To find docomo sim no. dial *1# or *580# or *124#
4. RELIANCE
On your reliance mobile dial *1# or *111#
5. IDEA
To find idea sim no. dial *1# or *789# or *100# or *131*1#
6. VODAFONE
On your vodafone mobile dial *555# or *555*0# or *111*2#
7. LOOP
To find loop mobile sim no. dial *1# or *001#
8. VIRGIN MOBILE
On your virgin mobile dial *1#
9. VIDEOCON
To find videocon mobile sim no. dial *1#
10. BSNL
Call 24365 and ask them And You just need to send a GPRSPRE to 53733 from your BSNL sim card.
11. UNINOR
To find videocon mobile sim no Dial Number *555#