See if someone could shed some light on the following...

I have designed a Banking application.
To further enhance my application I want to provide a new facility wherein if some customer gives a miss call to a particular no. with his/her Mobile No. which is the primary no. mentioned in the application he should receive an SMS regarding the Current balance in his A/c.
Can anyone help me as in how to proceed with this.

I am using SQL Server 2008 and .net Framework4.0