Office Web Apps are online versions of Microsoft's most popular office productivity programs which can be accessed via a web browser and an internet connection.
This cloud-based version of Office can then be used to view, edit and share Word, PowerPoint, Excel and OneNote documents online.
"If you live in the US, UK, Canada, or Ireland, you can head over to Office.live.com today to start viewing and editing Word, PowerPoint, Excel, and OneNote documents right in your web browser – and share them with your friends," said Jason More, lead program manager, Windows Live SkyDrive, in a blog.
The online version of Word initially only offers basic functions such as printing documents, copying and pasting text, inserting images and hyperlinks, creating tables and spellchecking.
Excel, PowerPoint and OneNote have even fewer features, although Microsoft said it plans to offer more functionality over time.
Office Web Apps also integrates the Windows Live SkyDrive storage service, which offers up to 25GB of online space.
You'll need a Windows Live ID in order to access the service. If you've got a Hotmail account or use other Microsoft web-based services, you'll already have one. Otherwise, you can register for one at home.live.com.
Microsoft said it was planning to roll out Office Web Apps across the world.
"You might not get the Web Apps in your favourite language yet, as we are still rolling out updates to different regions," added More.
See also: How to use Microsoft Office Web Apps