If you are looking for the most reliable iPhone app in the market today that carries the most comprehensive VoIP application for the iPhone, the Nimbuzz iPhone app is your best bet.

With free Wifi calls to instant messaging buddies already available, new additions include the introduction of a dial-pad and the ability to make VoIP calls to landlines and mobiles via Skype-Out, and Nimbuzz’s major SIP provider partners including Gizmo5, Vyke, and SIPgate over Wifi - effectively turning the iPod touch into an iPhone.

iPhone users without Wifi connection can make VoIP calls using Nimbuzz Dial-Up VoIP in over 50 countries.

Nimbuzz bridges the iPhone VoIP gap by allowing VoIP calls over 3G via its Dial-Up VoIP option in over 50 countries. It allows iPhone users to call (international) mobile and landlines at significantly reduced costs, by dialing a local access number that connects to anywhere in the world via Nimbuzz VoIP servers.

Another feature allows Twitter updates via the Personal Message option. Popular communities, including Skype, Windows Live Messenger, Yahoo! Messenger, ICQ, Google Talk, AIM, and social networks such as Facebook and MySpace are already supported with call and chat options.

(Source) Press