Now Upload Excel 2007 Files to Google Docs
If your clients sends an spreadsheet saved in the newer Excel 2007 format, you can upload that right away in Google Docs without conversion.
xlsx
View Excel 2007 Files without Microsoft Office
With Excel 2007 Viewer, you can open, view, and print Excel xlsx workbooks without requiring a copy of Microsoft Excel. You can also copy data from Excel Viewer to another program.