The Apple iPod Camera Connector is a small plug with a USB jack to download images from cameras, in both JPG and RAW/DNG formats. JPGS are viewable, but RAW formats are not, on the iPod itself. I had some issues, but none of serious despair.
I bought this iPod device in hopes of downloading imagery without a computer while traveling, and while it does work, there are some clear caveats. I recall finding a Wiki site some years ago that listed compatibility with media readers; alas I have no luck currently in locating that information. I had purchased a Belkin Hi-Speed USB 2.0 15-in-1 Media Reader & Writer for that purpose some years ago with an older iPod (Photo, I believe) to offload JPG files from a digital camera, and confirmed that indeed worked.
However, using that setup—with a card reader—did not work for either of my cameras: a Canon G9 and a Leica M8. Though the reader did not help (the fifth-generation iPod simply showed no photos available for download, and imported nothing), I did find that connecting the cameras directly to the iPod connector resulted in complete file downloads.
From there, you can easily copy over files from a disk-enabled iPod (check “Enable disk use” in iTunes), or import from a photo-editing application. There are a few caveats to this approach, namely, the speed of transfers from camera to iPod is fairly slow; transfers for four 10MP DNG file took approximately 1-2 minutes. Yes, four (4) pictures. That severely impacts camera battery life, and additionally, this process also requires power from the iPod. Although an issue, I pack an iGo charger with dual power connectors to charge most of the devices I tend to bring along. The upside is, importing from a computer is fairly quick.
Here’s another fairly extensive review of the connector. Also, here’s an interesting write-up on another storage technique.