As you may know, PHPExcel is built using an extensible model, supporting different input and output formats. The PHPExcel core class library features a spreadsheet engine, which is supported by IReader and IWriter instances used for reading and writing a spreadsheet to/from a file. Currently, PHPExcel supports writers for Excel2007, Excel5 (Excel 97+), CSV, HTML and PDF. Wouldnt it be nice if we could use PHPExcel to store a spreadsheet on Google Documents? Let's combine some technologies.
The two technologies in question are a standard install of the PHPExcel library and the Zend Framework (with its Zend_Gdata component). Using the component, a save() method is created and hooked into the IWriter interface of PHPExcel. When this save method is called, the Zend_Gdata component connects to the Documents service and uploads the resulting information for the account you supply.