Wireless carriers in the U.S., who are earning as much as 20 cents for sending and another 20 cents for receiving a text message, are worried that this profitable source of revenue will no longer be available to them, once Apple's new instant messaging application, iMessage, is released on Wednesday.

With iMessage in place, any user of an iPhone, iPad or even iPod touch can send an unlimited number of messages from their iOS 5 device to any other iOS 5 device, for free.

The launch of Apple's BlackBerry Messenger-like application may force service providers to revise or even scrap charges for text messages. 

According to a Topnews report, Craig Moffett, an analyst at Sanford C. Bernstein, estimated that the wireless industry pockets more than $20 billion in revenue from text messaging.

The new iMessage service may turn out to be a real killer for service providers, like Verizon, which gets $7 billion a year from texting fees, TG Daily reported.

According to a New York Times report, analysts say Apple is trying to duplicate the success of services like Research in Motion's (RiM) messenger app, which comes free with all BlackBerry smartphones and lets users send messages back and forth, as in an instant messaging conversation. It has engendered loyalty among BlackBerry users and has kept some from switching to an Apple or Android device.

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