Try recording a macro to your personal.xls file while applying the protection to one of the worksheets. Then just open each of the workbooks and run this macro.
You could record the first instance as a macro and either save it in your personal workbook or keep the original workbook open so that you can run the original macro in different workbooks.
I don't know whether you have locked/unlocked particular cells, so you might have to use relative referencing or mess about with the actual VBA code to get it to transfer properly (Alt+F11).