MobileFiles has been around for awhile, but they have just released the pro version which allows you to edit existing Excel files as well as create new ones. From their website EDIT! native Microsoft Excel 2003 documents just as you would on your desktop. Save the edited Excel file on your iPhone, send to your iDisk account remotely, or upload to your desktop using WiFi - all while maintaining perfect data integrity. The app costs $9.99 and is the first that I know of that allows you to edit and create any M$ Office documents. You can view Excel 2003 & 2007 files, create and edit Excel 2003 files, switch between different sheets, change inputs and recalculate, and use over 125 Excel functions. You can also change fonts and colors. The new version can view many more formats than its predecessor: Images: .jpg, .jpeg, .png, .tif, .tiff, .gif and .svg Microsoft Word: .doc and .docx Microsoft Excel: .xls and .xlsx Microsoft PowerPoint: .ppt and .pptx iWorks: Pages, Numbers and Keynote Adobe Acrobat: .pdf Web Pages: .htm and .html Web Archive: .mht RTF: .rtf Audio: .mp3 Movies: standard iPhone format Hopefully, they will be providing updates to allow editing of other Office suite apps and iWork in the near future. I, for one, am stoked about this. I've been dying for a way to edit spreadsheets on the go.