I have had success (of sorts) with the Kensington Micro usb dongle. It really is pretty tiny.
I use it with a Vista Home Premium Desktop. I couched it as "of sorts" since the drivers were not all that easy to deal with and the ones on the cd that came with it did NOT work. It did give me error messages but then connected anyway. I use it with Desktop Manager. I was also able to actually transfer a file using it apart from DM but that was just to see if it could be done.
Here's a link: http://us.kensington.com/html/14409.html