According to Petr Bobek, product manager at Microsoft’s Czech Republic subsidiary, let it slip at a press event that official Microsoft Office apps will come to iOS  and Android  in March 2013. The Verge corroborated the story by claiming to get their hands on a press release by Microsoft Czech Republic that states:
In addition to Windows, Office will be also available on other operating systems, Windows Phone, Windows RT, Mac OS, Android, iOS and Symbian.
For its part, Microsoft  is sending mixed singles about the issue of Office on mobile devices. On one hand, Microsoft told The Verge: “We have said previously Office Mobile will work across Windows Phones, Android phones and iOS.” On the other hand, Microsoft released an official statement saying: “The information shared by our Czech subsidiary is not accurate. We do not have anything further to share at this time.” So it isn’t entirely clear what is going on in Redmond.
If I were a betting man (I’m not), I would bet that while it is possible that March 2013 is not the correct date for the release of Office for mobile, Microsoft is actively working on Office for mobile and will release it sometime next year… or else risk losing their stranglehold on office suites.