Definitely you can use your excel spreadsheets on iPhone 4, iPad, Android or any other iOS devices. Every one has mobile devices in their pockets, so it’s easy to carry them, you don’t need to carry your laptops.You can also create an Excel sheet from the data collected via application and then email that sheet as an email attachment.
Lets say you have a spreadsheet has a Main Menu, 10 data entry / calculation tabs assuming that each one would be a page or button within the mobile app and a Summary report Page compiling a total value, nice colorful charts and couple of graphs from each of the 10 tabs. This can be converted into a Native iOS application or Android Application.