Ping! is an instant messenger exclusively for iPhone users
Ping! is a instant messaging client for the iPhone that looks and feels like the built in iPhone SMS client. It aims to provide free iPhone to iPhone (and iPod touch on wifi) messaging.
Once youve download the (currently free) app and selected a username, you can invite/find friends and family you know own an iPhone or iPod touch, and youre ready to go.
Once youve started a conversation, the application works just like the SMS client except its free, instant and works internationally at no extra cost (aside from your international roaming costs that is). Whenever you receive a message youll receive a push notification and you can respond just as you would with SMS.
Get this quick, a similar app called Whatsapp was free and now charging 59p
Link To website - Tried to change direct link but no success:http://www.pingmessaging.com/Ping!/Ping!.html