AIR-Time Transfer

I am Currently in Canada but I am from Cameroon in Africa. There are 2 GSM providers in CAMEROON (MTN and ORANGE). They both offer a service the allow customers to share airtime (Calling credit) among them eg. I have $ 10 in my phone, I can send $ 5 to my friend. This is done by sending him a message with some specific code depending on the provider. It has now become a business whereby instead of selling scratching cards to pays as you go customers, the GSM providers sell special SIM cards to whole sellers, they can then resell the credit in they SIM cards to pays as you go customers by sending them a text message specifying the amount purchased. I want to be able to do this business (Retailing) From Canada to Cameroon. This is a website that does what I want to do. [login to view URL] I have an idea of the architecture but I need someone who knows everything about it so I can focus on the marketing side of my business. I know I would need a VOIP GSM GATEWAY, 2 server.... Thanks.