Facebook Messenger has been announced by the social network giant, a web-powered instant messenger in the same vein as BBM, and one that pips Apple's forthcoming iMessage service to the IM post.

The app is a standalone one - not just an extension of the current Facebook apps - and is landing for both iOS and Android.

It ties in with the Message side of your Facebook persona, so will bring in all your Facebook conversations no matter where they took place and it also offers additional features like one-click access to messages, location mapping, and the ability to message groups and mobile contacts.

If your message target is a Facebook friend already they will receive the message through the social network, but you can also message non-Facebook friends with notes that will send as texts.

"When you're on the go, coordinating a bunch of people can be tricky, especially if plans change at the last minute," said Lucy Zhang, Beluga co-founder and Facebook engineer.

"With Messenger, you can quickly start a group conversation and message everyone at once. If you choose to add your location, the people you're messaging with can easily find each other on the map. You can also attach photos, so everyone else can see and comment on what you're looking at."

Facebook Messenger is showing up in the US App Store at the moment, but not the UK one - and there's no sign of it in the UK Android Market as of yet.

But Facebook is saying that it will be available "today" so keep checking back for access.

There are also reports doing the rounds already that the Messenger app contains hidden code for video chat options, so expect a pretty big update somewhere down the line too.