Broadband and advancements in voice technologies are changing the way we used to communicate. Long distance telephone calls are made cheaper by services like skype and Jaxter. The same technology is affecting mobile services also. Most new phones have lots of memory and processing power. And with the data services on mobiles improving, its possible to place internet phone calls via mobiles.
J2me provides a SIP API specifically for this purpose. Using this API an application can be developed that can communicate with any SIP service and that includes most of the web telephony people. The costs will come down for long distance calls. The service can use the wifi facility available on most new generation handsets. Local wifi service can use the internet and also provide a means to make phone calls.