Apple has started rolling out its productivity suite iWork to iCloud, the company cloud solution. So if you have received an invitation, you can use your Apple ID and password to log-in to http://iCloud.com and experience for free the Web version of Pages, Numbers and Keynote, which are the equivalence MS Word, MS Excel and MS PowerPoint respectively. Since this is a browser-based version, it should work regardless what platform you are using. The stand alone for Mac cost $20 each and the iPad/ iPhone version costs $10 each.
The solution compete with Google Drive [Free) and Microsoft Office 365 (subscription-based). However, iWork for iCloud is still lacking collaboration feature that its competitors have.