I would like to provide private lablebulk sms messeging from my web site to my customers. They can either use the utility on my site or the can incorporate it on their web applications using API (mainly PHP)

So I think there is two ways to do it

1- Be a reseller to some sms web gateways companies
So is there any company that provide such a service where I can resell their bulk sms, and still can still it appears I am providing the service (specially in the programming)

2- Setting up my own sms gateway
But what are the requirements?
How can I do it?
is there any manuals, how-to's, tutorials, user guides?