Microsoft took their time, but the web is abuzz with news that Office is going to be available as a fully web-based service. According to ReadWriteWeb:
These will be “lightweight versions”, but Microsoft told us yesterday that they’ll still have rich functionality and will be comparable to Google’s suite of online office applications. The apps will enable users to create, edit and collaborate on Microsoft Office documents through the browser. The apps will work in IE, Firefox and Safari browsers (no word on whether Google Chrome will be supported). Microsoft clarified in an email that these apps will use HTML and AJAX, but also Silverlight components.
The next release of Microsoft Office will include browser-based versions of Word, Excel, PowerPoint and OneNote.