This code creates the file temp.xls in the desktop but it uses the SpecialFolders property, which is very useful sometimes!
set WshShell = WScript.CreateObject("WScript.Shell")
strDesktop = WshShell.SpecialFolders("Desktop")
set objExcel = CreateObject("Excel.Application")
Set objWorkbook = objExcel.Workbooks.Add()
objWorkbook.SaveAs(strDesktop & "\temp.xls")