One of the constant headaches of developers especially when dealing with applications that will require massive data upload such as stock exchange data, school results, name list, mailing lists and other spreadsheets is how to import these data directly into the database or at least convert it into an array and do whatever you wish to after that.

There are many classes that can handle this online, however, there are PROs and CONs to using these classes. I have found out from experience that PHPExcel is simply one of the best classes to handle this. This library can read do a lot of work, however, I am focusing on the ability to read excel data (CSV,XLS,XLSX) into PHP arrays - both active worksheet and entire worksheets.

You can get the source code here