Hi,
Maybe I missing the point but if your intention is only to convert excel file to CSV file then this functionality is available in MS Excel itself. You just need to click on Save As and select CSV from "Save as type" drop-down menu.
This is a free tip - I bided just to be able to give you this info.
If I am missing the point - I apologize for that.
Cheers,
Feliks.
PS. Anyway if need so php script - you can let me known :)