http://box.net/  is offering this great free deal.

If you’ve used dropbox, this works in a similar fashion.

“Looking for a way to boost productivity and simplify your workflow without leaving the Microsoft Office programs you use everyday? The all-new Box for Office helps you:

- Open a file stored on Box, edit locally, save back to the cloud
- Open a new or existing desktop file in Word, PowerPoint, or Excel, then save directly to Box
- Easily share files with Box from within Office”  - box.net

You can also work with box from Android.