Windows Live Essentials is a collection of tools available free of charge from Microsoft, many of which have a strong focus on the internet, sharing and social networking.
"Many of you have been asking for Facebook chat, and it's finally here," said Microsoft's Chris Jones in a blog.
"More than half of all Messenger customers also use Facebook. With the new Facebook chat integration, you now also have one place to chat with all your friends."
Web users downloading the latest version of Windows Live Messenger will be asked if they want to connect with their Facebook friends through the messenging app, while those who already use Windows Live Messenger can opt to connect with their Facebook account via their profile page.
Microsoft also said the upgraded version of Messenger was faster than previous editions and has a more efficient video chat function that uses 30 percent less CPU resources.
According to Mickael Remond, CEO of ProcessOne, the integration of Facebook into Messenger shows that social networks are increasingly becoming the preferred communications medium for a lot of people, as opposed to traditional instant messaging.
"It also shows the power of open protocols such as XMPP (on which Facebook Chat is based) for instant messaging and chat as it allows for communication between different messaging platforms, which is increasingly the way web communications is going."