I also ordered the iRiver USB host cable. It is a tiny little cable, great for carrying around without the bulk of the full-sized cables. So far, I have plugged in:
1. a Compaq USB full sized keyboard, and it worked without any configurations of any sort! Just plugged it in, and opened Hancom Word, and started typing.
2. a Targus numeric keypad. It also worked beautifully without configuration of any kind.
Other USB devices (Gravis GamePad Pro USB, Belkin USB Optical mouse, Logitech USB WebCam) also detect, and possibly will work if drivers and application support are worked on.