Hi all,
Not that I am an authority on the subject but I do know this:
USB is great for plugging things into a PC as it is a "host" and all the things you plug into it are "devices"
It takes much more "horsepower" and resources to create a "host" than a "device"
This is a problem for most PDA's which are only devices and not hosts i.e you can plug them into a PC (for syncing etc) but you can't plug devices into them.
Most microcontrollers that have USB are only devices (JB included)
I do not know about the UF32 which alex claims has a special memory stick host.
The OTG spec (On The Go) is supposed to address this issue but it is still new (i.e. not much actual hardware that supports it).
There, thats my 2 bob's worth!
BR Peg