Microsoft's CEO, Steve Ballmer, today announced the next generation of Windows Live Messenger, known as Windows Live Messenger Wave 4 to us geeks. Various rumours and leaks have previously circulated the Internet in anticipation of the update.

Microsoft have been expressing their love for the cloud recently, with online service support for things like Office, and of course emphasizing the hugely popular Xbox Live service.

The new Windows Live Messenger takes this cloud offering a step further than just goofy chats with your mates. The client will offer a range of sharing options, tabbed conversations and support for HD video chat online to over 320 million users of the service.

There is also support for social networks (Facebook, LinkedIn, MySpace) updates to feed through into Messenger, so rather than having to open a browser to check for updates, you'll be able to see that your friend has just posted pictures of their cat. You'll be able to comment directly on Facebook stuff too, all from within Messenger.

Photo sharing and video sharing can now be done right from the IM window so you can share, discuss, or watch together, pulling in videos from YouTube. One neat trick is being able to share photos whilst video chatting too, so you can see the other person's response.

Microsoft seemed to be really stoked about the Facebook integration and is looking to get in on some of the action – with Facebook's 400 million users, who wouldn't want a piece of that? We asked Microsoft whether you'd be able to chat directly with people using the Facebook Chat client, and our MS guy told us that was something that was intended for the future.

Tabbed conversations will make it easy to run concurrent conversations, a facility that Skype already offers, and with the integration of HD video chat, it looks like Microsoft wants to reclaim some of this territory too. We asked whether there would be any sort of network diagnostic feature as there is with Skype, as the biggest issue here is likely to be bandwidth – this drew a blank, so if we hear more, we'll update this story with the details. Obviously, you'll need the right hardware too.

Tabbed conversations will also be supported in the browser-based client, so you will be able to use your Windows Messenger from any computer without installing software – you simply log in and off you go. You'll also get better integration with Windows 7, with a jump menu to let you get straight to the goodness and there will be real time event alerts which pop-up in the corner.

Third-party sites will also be able to tap in on Messenger APIs to take advantage of some of the functionality and provide a Messenger service from their own site. Microsoft are also launching a plug-in for Internet Explorer that will let you quickly share web content with your Messenger buddies.

Privacy has been considered, so you'll be able to drill down and find out exactly what each individual can see of your stuff. You'll be able define who your favourite friends are too, so their updates get precedence, giving you quick access to the people who matter the most.

Of course this goodness is aimed at your Windows PC, but Microsoft did tell us that Mac Messenger would be getting an update "soon", but couldn't detail what it would contain. Microsoft also told us there would be new and updated mobile phone applications, name dropping iPhone, BlackBerry and Nokia, and of course native support in Windows Phone 7.

Windows Live Messenger Wave 4 is expected to hit in the late summer, but you can check out the preview here. (UPDATE: we're still waiting for this link to go live - in the meantime, we've added a promo video below.)