First, you need to be aware of the entities involved in such set-ups. From your explanation, it appears that you are interested in the innards on the Application Server end. Those Applications still have to engage PRSPs for connection to the Mobile Networks. *Mobile Providers* --------- *PRSPs* | SMS-C/ |<------http------> APP1 | USSD-GW |<-----xmlRpc-----> APP2 *HANDSET* <----- ss7 ----> | SERVER |<------smpp------> APP3 | or |<------vXML------> APP4 | SWITCH |<---witchcraft---> APP5 --------- In this case, I'd say scout for the business clients to the PRSPs . Of course some of the apps are hosted in-house by the Mobile Providers, and I suspect that some PRSPs may also double up as app-server owners. Tony.