Electronista provided a roundup of the findings yesterday, first noting that one test by TidBITS discovered that the kit will work with most any USB headphone, headset or microphone. This makes it possible to either listen to music or take a VoIP call through off-the-shelf computer accessories. The call quality via VoIP was reportedly "terrific," making it more appealing to use Skype if you don't have a Bluetooth headsets.
Meanwhile, TUAW found that USB keyboards will work as well, although this was partly expected given the functionality of the official iPad Keyboard Dock. The convenience of the USB keyboard is also reduced as there's no stand when using the adapter.
For its intended role, the adapter imports images to the iPad's Photos app when plugged in. Besides supporting RAW from high-end cameras, iLounge notes that the iPad will import any captured photos at full 2048x1536 resolution, including the EXIF metadata from the original shot.
Video is also supported with tools that let photographers trim videos much as they do with the iPhone 3GS' simple editor. Clips are cut short, however. Any video larger than 640x480 and 5MB will be shrunk in resolution and length to fit the length.
A video demoing the iPad Camera Connection kid can be seen above.