Application for Iphone 4 and Ipad / Dialer for VOIP

We are a VOIP company. We need a software for IPHONE and IPAD that would combine with our line of work. To use our service of dialing numbers abroad the user must first dial +381112023000 and then wait for 6 sec and than he must dial the number abroad. On normal mobile phones we give our customers SIM dialer that goes together with regular SIM card, and when customer goes to phone book on his telephone and dials his number, our SIM dialer automaticaly first dials our switchboard +381112023000 and then it automaticaly dials the required number. Now with Iphone 4 and mini sim card we can not insert our sim dialers inside the Iphone and now we have to resolve it by software that would be free aplication that we would like to offer through App store. If you can make this software we would be more than glad to give you more details and this job. Regards ABATEL