Powered by Google docs lets you export a Google spreadsheet to Excel, Open Office, or PDF.
I use a Google Docs spreadsheet for Gas Mileage. For me, the best feature is that Google Spreadsheets has a form feature which I setup with lots of drop-down multiple-choice selections, as well as a few open text box fields. So, using my mobile phones browser which I have the spreadsheets form web page bookmarked, I go to this spread-sheet's form web page and select & input data in the form fields which when I submit the form, it puts the data into the spreadsheet. To me, viewing the Google Docs spreadsheet form on the mobile browser is much easier to view on the mobile phone than a spreadsheet was. And, I have the form fields setup as 'required fields' so that it won't allow me to submit data unless I have all of the fields populated with data. Also, the form puts a timestamp of when I submitted the data in the first column of the spreadsheet as well.
Then when I go to the Google Spreadsheet on my desktop, I can populate the remaining fields with the formulas that performs all the calculations from the data fields which I inputted via the form.
All Powered by Google Docs which is FREE!