Microsoft has already announced about the next version of Microsoft Office application. Since then we have seen some leaked screen shots of it. Here is the new Office logo and new screen shots. You can notice that it has new interface that supports touch screen as well improved features.
Code name for new MS Office is Office 15, however according to leaked images it may named as Microsoft Office 2013. It also revealed the new logo.
Here are some images of Office web Application from LiveSide.