VoIP apps for the iPhone : Fring

Fring is another popular mobile VoIP client and it allows you to integrate other popular social outlets such as Skype, ICQ, Twitter and AIM. Fring provides an excellent way to keep most of your social networking and instant messaging all bundled in one app. You can make free calls to any other VoIP, Fring or Skype user. Fring offers a special version for visually impaired users as well.