The usage of internet by mobile phone is always increasing (by Wifi or services offered by mobile providers) and VOIP mobile applications became very popular, they allow to call or send messages free or at cheapest price.
Let’s see the best VOIP apps:
Skype (iPhone/iPod touch, Symbian, Android); free calls/messages to other Skype users (will be no more free from the end of 2010) and low cost calls to mobile and landlines, low cost sms thanks to SkypeOut service
Truphone (iPhone, Symbian, Android, BlackBerry) free calls/messages to other Truphone users and to some IMs supported (Skype, Google Talk, MSN, Facebook); low cost sms and calls to mobile and landlines
Tango (iPhone, Android and pc) free calls to other Tango users
HeyWire it allows to send free sms to cellphones and messages to IMs (MSN, Facebook, Twitter etc…) available as iPhone app or for Windows and Mac, soon available also for Android, Blackberry, Google TV
Viber free calls and messages, available for main platforms (Android, iOS , Windows, Mac).
LINE free messages, calls and video calls, available for main platforms (Android, iOS , Windows, Mac).