Value Added Services setup ideas

Hello,
I am about to go into Value Added Services providing. I came to understand that I will be making use of a computer program and that there are available transmission protocols like the SMPP.
However, my questions are:
* which hardwares do I need to purchase (please list all).
* the software its going to run on, will be to specification. A link to a reliable developer will be appreciated.

The services will be provided like this:
* a mobile phone user sends a sms to a particular short code.
* the content of the sms will be delivered to my system which then acts on the message.
* from the decision made, my system may decide to send another message to one or more network service providers.
Any useful information would help.
Thanks.