We got wind of it weeks ago, but today has seen the official launch of Facebook Chat.

The new tool, which is already being mooted as a rival to the likes of Microsoft's Windows Live Messenger, is accessible on profile pages.

A chat bar at the foot of the browser allows members to have a private conversation with one another, rather than rely on email messages or wall posts.

Facebookers can "chat" to any of their friends that are online and the service doesn't install any client software so it can be accessed from any computer connected up to the Internet.

"Chat is by no means a new concept, as instant messaging systems have been around for over a decade", says Josh Wiseman, engineering lead at Facebook on the company's blog.

"But just as other features on Facebook have allowed friends to communicate more efficiently than before, we hope Facebook Chat will make it easier to connect instantly."