Google QuickOffice Pro HD
Like Microsoft's CloudOn app and service, QuickOffice Pro HD lets you create, edit and track all Microsoft Office documents, spreadsheets, and presentations whether they are locally stored or stored on the cloud via services such as Google Drive.
Supported documents include Microsoft Word 1997-2010, Microsoft Excel 1997-2010 and Microsoft PowerPoint 1997-2010, along with the capability to track changes, add comments and perform spellcheck within those documents. Additionally, QuickOffice Pro HD allows files to be saved as PDFs and printed using iOS AirPrint. Microsoft SharePoint files can also be opened, edited and saved.