Mac OS Internet Telephones

• Asterisk  - Complete version of PBX in software runs on Linux and other Unix-based machines. Offers voice in three protocols and can interact with many standard telephone systems.
• Empower Pro Internet Phone  - Enables users to share peer-to-peer telephone communications over the internet.
• RogerWilco  - Designed so gamers could share voice communications during space battles, RogerWilco offers peer-to-peer voice telephony.
• SJ Labs: SJphone  - Delivers high-quality peer-to-peer voice communications.
• Skype  - Presents free peer-to-peer telephone communications as well as low-cost integration to land lines.
• XMeeting Video Conferencing for Mac OS X  - Allows users to share voice and video communications.