Using Office Web Apps, you can view as well as edit Office documents on any computer and since these apps work inside the browser, you can even edit Office files on a Mac without requiring the Office software.
Sign-up for Office Web Apps
If you are not signed-up with Office Web Apps yet, here’s another opportunity:
Step 1: Create a Windows Live ID if you don’t have one already or if your existing Live ID uses a country other than US.
Step 2: While signing up, make sure you select "United States" for the Country field else the program won’t let you in. You may use NY for the State field and 10001 for the Zip Code.
Step 3. Once your Live ID is setup, just click this link, accept the license agreement and the Office Web Apps Technical Preview will be activated for your Live ID.
If you face any issues while executing Step 3, here’s an alternate approach – go to skydrive.live.com, upload any dummy Word file to the Documents folder and you should then see an invite to join the Office Web Apps programs. That’s it. Thanks Sean.