What does that mean? Does iPhone/iPod have some kind of protocol of their own to communicate over USB?
I don't know how you would build it in. There are other programs that run on a MAC or PC that access the filesystem of the iPod/iPhone over the USB cable, as well as programs that emulate NICs and serial interfaces over USB. I would guess that you either would have to build support for the methods used to access the device over USB into the WinSCP as an additional protocol or function, or an external program would be needed to make the device accessible via a private IP number so the USB interface looked like a NIC with an IP address. I know it's apples v oranges, but the iPhoneBrowser access the iPhone filesystem over the USB, albeit it does not do generic FTP/SCP functions over IP either. Your interface is much friendlier than the iPhoneBrowser's interface and your file management functionality is more robust.