TORONTO - Research in Motion's BlackBerry Messenger (TSX:RIM) will have to take on yet another competitor. And this time, the challenger is as big as they come.

Apple announced Monday that it's soon launching iMessage for the iPhone, iPod touch and iPad, an instant chat app for exchanging text messages, photos and videos.

Its features mimic much of what BlackBerry users have come to love about the popular BBM program, including prompts showing when a message has been received and read, and when other users are typing. Apple says all messages will be securely encrypted.

While BlackBerrys took over the corporate world through its mastery of mobile email, it was BBM that really helped RIM get the devices into the hands of consumers.

Last month, RIM said it had amassed 43 million active users of BBM, who were sending 100 billion messages a month. About 70 per cent of BBM users were using the program daily. The user base was growing by about two million users a month and had more than doubled in the past 12 months.

Much of RIM's consumer marketing has focused on BBM, and how the likes of surfers, flirting singles, barbers and street racers in India are hooked on the service.

"Everybody knows that BlackBerry Messenger is a very popular product," says Deloitte Canada analyst Duncan Stewart.

"Now everybody else who wants to introduce a robust instant messaging product tries to have features that are as close a copy as BBM as they can get."

There are already a number of BBM competitors on the app market, including Kik and PingChat!, which are both developed in Canada.

Those apps were programmed so users on Apple, BlackBerry and Google's Android platforms could chat with each other. Kik stopped accepting new BlackBerry users after a patent infringement lawsuit was launched by RIM.

It's been rumoured that BBM could be made available on other platforms but RIM won't comment on those reports.

Stewart says it would make sense for RIM to broaden its user base if Apple's iMessage really takes off.

"If it's no longer differentiated keeping it locked onto your phone and nobody else's doesn't do much good."

IMessage will be available with the release of its new mobile operating system, iOS 5, in the fall.

Stewart says iMessage's ability to woo BBM users will come down to execution. BBM's instantaneous response time will have to be matched for iMessage to have the same appeal.

"If you've worked with BBM even a little bit you know it's really like having someone in the room with you," Stewart says.

"Even very, very, very small delays in the network could in fact create a substantially different user experience."

Some of the other instant chat apps have also suffered from battery drain issues, another factor iMessage will have to avoid.