iPhone Apps to make audio calls over internet using VOIP

Fring was a pioneering mobile application that unified communication across popular platforms like Skype, MSN Messenger, ICQ, and Google Talk directly from your iPhone, offering voice calls, video calls, and messaging. ...more

Linphone is a free and open-source Voice over IP (VoIP) application and SIP client available on multiple platforms. It enables encrypted voice and video calls, instant messaging, and file sharing, offering a privacy-focused communication solution. ...more

Voxeet is a robust web conferencing platform that elevates virtual collaboration with its unique high-definition 3D audio technology, providing an immersive meeting experience. It offers a comprehensive suite of communication tools, including video conferencing, screen sharing, integrated file sharing, and various chat functionalities, designed to facilitate seamless interaction for teams of all sizes. ...more

Skype is a versatile communication platform offering free voice and video calls to other Skype users, as well as affordable calls to landlines and mobile phones worldwide. It provides instant messaging, file sharing, and screen sharing features, making it a comprehensive tool for personal and professional connectivity across various devices. ...more