Hi,
I can develop the software.
But just needs some clarification.
1. Sending bulk sms is not free. The software will use a third party to send sms, who will charge for it. So you will have to buy a package from the third party depending upon your usage and facilities required.
2. What are your expected modes of sending. Will the numbers be stored in a file, database, xml file.
3. Whether you want a desktop app or a web based. What features do you want? What user interface do you expect?
I would be pleased to work with you.