I dont think our phone's java platforms would support such a java application, there's no api to support access to the phone's calling feature "hense there's no proper VOIP applications", but i think the new jp-8 has such an api ;) i know jp-8 has SMSapi so some of the newer models will soon be able to send encrypted/decrypted sms, i think it also has the calling api (not sure though), but our k750/w810 are jp-5 and support no such api's :(