Wrote this little diddy to convert an Excel 2003 file to Excel 2010 file.
' http://technet.microsoft.com/en-us/library/ff198017.aspx
Const xlExcel12 = 50
Set oExcel = CreateObject("Excel.Application")
' Set below value to false to hide the Excel window
oExcel.Visible = True
' Convert
Set oWorkbook = oExcel.Workbooks.Open("C:\filename.xls")
Set oWorksheet = oWorkbook.Worksheets(1)
oWorkbook.SaveAs "C:\filename.xlsb", xlExcel12
' End
oExcel.quit (oWorkbook.Close)
