When the iPad was released, many decried its lack of connectivity. In keeping with its position in the iPhone OS lineup, the iPad is designed to be a companion to a full-fledged computer, not a replacement--you can't plug in any external gadgets like hard drives, USB flash drives, MP3 players (including iPods), printers, or cameras. Apple does offer the $30 Camera Connection Kit, however--and people have just started figuring out what it can do.
The Camera Connection Kit consists of two dongles, one with USB and one with a slot for an SD card. It's designed purely for cameras, and imports photos directly to the Photos app (no messing about with albums or files). But that USB is a little more promising--what else can connect to the iPad?
TidBits discovered  you can connect pretty much any USB headset, headphones, or microphone, which turns the iPad into a pretty decent little Skype device (with better quality sound than you'd get with Bluetooth). USB keyboards also work , but are incredibly awkward since the dongle renders the iPad unable to sit upright in a dock.
As for photos, the iPad will take all your photos at full resolution, including EXIF data, but videos don't fare as well. Videos will be shrunk down to a maximum of 5MB and a 640x480 resolution--bad news for those with even a modern pocket camcorder like those made by Flip. Overall it's not great news--we were kind of hoping the USB dongle would be more useful than just supporting microphones. But it's not really unexpected.