Satio App: Skype
Skype lets you make free Skype-to-Skype calls and IM on 3G or WiFi. Save money on calls and texts abroad. Share files. It’s free to use Skype over WiFi. With a mobile data connection, operator charges may apply.
The call quality is very good over a fast internet connection. Overall a nice VoIP app. Click here to go to the download page.