I bought myself this thing:
It is for an iPod allowing it to connect digital camera over USB.
Works fine with my canon, but of course i want to try more.
My old Pendrive Kingston Data Traveller 256MB (year 2004) works directly.
I also tried a Western Digital 80GB 2.5 inch harddrive in an USB enclosure (ICY BOX USB + FireWire), it works with additional external USB power.
Unfortunately my HAMA 35 in 1 media reader is not supported, i assume that it needs more power from the usb port. (camera has its own battery, pendrive does not require too much, hard drive also has its own power supply).
I need to give it a try with USB hub that has external power supply.