I receive lots of SMS from the operators with some TEXT as sender number instead of mobile numbers as the sender address. Please let me know how is that possible from a mobile phone or any other GSM modem. Is it that they modify the SMS message header or do any other tweaks to achieve this.
Share your ideas about this hack !!!

hmm... sorry kuberan, but i may not be able to help you here. i am a heavy user of my mobile phone, and i have taken it apart, i heavily customise it.

so far, though, i have not come across something like this.

are you sure that this was send through a mobile phone? are you sure this is not just from your operators as standard routine?

ok, you seem to think it is. well, nowadays, you can send text messages via a computer!

just go to http://www.ipipi.com/

this service allows you to send or recieve text messages from a computer.

so i am thinking: what most phone operators probably do is have somewhere a database with all of their customers' numbers, and then when necessary to send a message to all of them, they just send via services such as this.

once again, i am not certain of this. but it is the best i can think of.