No, this is not a new set of applications you’ll have to download via the App Store. This version of Microsoft Office will be a set of web apps that will be accessible through various internet browsers such as Internet Explorer, FireFox and even the Safari browser on the Mac.
It’s actually meant for internet users in general and not just the iPhone, but considering how Apple's little mobile phone is such a great portable internet device, the implications of having such an application available for the iPhone simply cannot be overlooked. With the Microsoft Web Office suite, iPhone users can definitely do more on their beloved mobile device than just playing games and listening to music or watching YouTube videos.
A private technology preview of this Microsoft Web Office will be made available towards the end of this year, but the exact public release date is yet to be known. 2009 has been mentioned as its debut year. Let’s just keep our fingers crossed that it doesn’t follow in the trend of Windows 7 which has been plagued with one postponement after another.