Now it is time for us to make voip calls from iPhone/iTouch 2nd generation. This app supports most features we want as a sip phone: (1) speaker phone (2) true DTMF (3) voice mail (4) multiple sip servers (5) ringtones and more ... Compare to fring, in voice quality, it has better voice quality and less delay. And it has more features as a phone. More important, you can search for lower rate sip providers and use them as your service provider.