The bottom end of the iPod shuffle detachs to reveal a USB connector. Apple warns that you must install the iTunes software before plugging into a computer for the first time, but this is not necessary (at least on a PC) and the shuffle appears as a standard drive when inserted.
Due to the width of the shuffle, some people may experience difficulties in finding a USB port that has enough clearance. The test computer contains 4 USB ports so this was not a problem, but it was not possible to insert the shuffle in a port adjacent to one already in use. Apple provide a USB extender, at a cost, but there are also third-party products that will work equally as well.
Data files can be transferred to the shuffle via any standard method, and it can be used as a portable data drive, without needing drivers. Although advertised as being USB2.0, the transfer speed is slow, and I would not be surprised if it was actually USB1.0
Music can only be transferred by an iPod-supporting music program. The reason for this is that the iPod requires a specific directory structure and maintains an on-board database of music files. It seems this is standard across all varieties of iPod.
The iPod shuffle natively supports AAC, MP3, WAV, and Audible e-book formats. Any other formats, such as WMV, must be converted before transferring.
The iPod shuffle will automatically charge from the USB port when inserted, should it provide enough power. There is no other way to charge the shuffle, so you should make sure your USB ports are powered.