Enjoy the wonders of Skype on your iPhone Skype 4.0

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Skype for iOS has reached version 4, which finally sees video calls added to the service. This incredibly popular app now lets iPhone and iPad users make video calls over WiFi and 3G networks.
Skype has always had a great interface on the iPhone, and that is still true. The big usability change is that you can now use all its features wherever you have 3G. Chat, call or video chat any of your skype contacts, whatever platform they are on. This cross-compatibilty and 3G puts Skype ahead of Apple's own FaceTime in terms of usability

WhatsApp Messenger/3G Smartphone to smartphone messaging

3G Smartphone to smartphone messaging

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When you install WhatsApp Messenger, you have to enter your telephone number, then enter a code you receive via SMS. From then the app syncs with your iPhone contacts - anyone who owns the app will have a tab attached. Touch a contact who doesn't have WhatsApp Messenger and you'll be able to send them an invite.