Hey Owen,
As you may already know, since you are using an Android device I would recommend you using Google Spreadsheet. It is a free and online version of Excel created by Google. Any changes would be automatically saved to your Gmail. You can share, set restrictions, and use many of its other options.
If you are determined to use the .xls format, you can download any Android application that would support you to do so: “Kingsoft Office”, “Documents To Go”, “Olive Office” and many more.
Please feel free to ask if you would want me to elaborate on how to use Google Spreadsheet more Professionally.
