Facebook has launched its own dedicated instant messaging

Facebook takes on Blackberry Messenger with new app.

Facebook has launched its own dedicated instant messaging mobile app in a bid to take on Blackberry Messenger.

The app, which is called Facebook Messenger, launched yesterday in the US only, and lets members of the social networking site send instant messages on their mobile for free to anyone in their 'friends' list.

In what is a direct bid to rival Blackberry’s hugely popular Messenger service (BBM), the new Facebook app, also allows people to send messages to friends on their mobile contacts list and push out group messages too. The timing is apt, as BBM has just received a huge spate of publicity, having become the communication tool of choice for many London rioters, as well as a useful channel for those trying to warn each other away from areas dominated by violence. RIM, the parent company of the phone, has agreed to work with police on their investigations trying to locate and pin down the London rioters.

BBM is understood to have more than 45 million users around the world. Facebook, with more than 750 million users worldwide, will be hoping to be able to steal away some of it market share in the growing mobile instant messenger market. Google+, the search giant’s new social network, introduced Huddle earlier this year – which allows instant messaging (group and one-to-one) on mobiles and iMessage, Apple’s instant mobile messaging service, is coming out later this year, forming a central part of the new iOS 5’s software.

The free Facebook Messenger app is available on both Android and iOS devices, but there are no dates set for when it will be made available outside of the US.

"More and more of us rely on our phones to send and receive messages. But it isn't always easy to know the best way to reach someone on their phone. Should you send an email or text? Which will they check first? Did they even get your last message?" wrote Facebook engineer Lucy Zhang in a blog post explaining the new service. "We think messaging should be easier than that. You should be able to write a message, click 'Send' and know that you will reach the person right away."

Zhang originally created Beluga, the group messaging service acquired by Facebook earlier this year. The majority of the technology underpinning the new Facebook app has come from Beluga’s code.