Here is the situation, you have installed iTunes on your computer and when you connect you iPhones, there is a message saying : "Cannot find the driver". You must have think that you are lacking of iPhones driver and try to googling abound download iPhones driver.
Nah... all iPhones drivers are bundled with iTunes. The only problem is that latest iTunes is working on OS Windows XP Service Pack 2 or higher (for PC users).
Thus, if you installed iTunes on lower OS version, it can not find necessary driver for the iTunes to connect with iPhones. So, not because you do not have iPhones driver. USBAAPL . SYS is the iPhones driver but USBBPL . SYS is already bundled in iTunes. So, you do not need to download USBAAPL . SYS separately.
USBAAPL.SYS, download now