Mariner Calc for the iphone gives you the abilty to view and edit Microsoft Excel documents directly from your phone.

Mariner Calc also includes 24 math functions, 18 finance functions, 17 trig functions, 13 statistics functions, 14 lookup functions, plus logic, date, text and info functions with many more on the way. It also supports splitting panes and freezing, as well as creating borders and changing fonts, colors and alignment. Landscape and portrait views are both available.

1. View native excel files (.xls format Excel 97 and up)
2. Edit native Excel files (.xls format Excel 97 and up)
3. Wirelessly transfer files to and from your computer
4. 32,000 by 256 column support
5. Supports cut, copy, paste, undo, and redo
6. 145 functions!
7. Support for multiple sheets
8. CocoaTouch native application

If you find yourself needed to view excel documents on your phone then this app is a no brianer.  It has a hefty price tag, for now, but even so as business class application it’s well worth the money.

iTunes App Store Link $9.99