The USB connector from the Camera Connection Kit needs to be plugged into the iPad you want to share the photos and videos to (see the iPad on left in the photo below). The Dock connector cord is used to connect the two iPads together. The connector kit works with iPad 1, 2 and 3 with the old style dock connector.
As soon as they are both plugged in, the photo app on your iPad you are “transferring to” will open immediately and shows an extra Camera tab at the top of the screen. The photos will start to populate the screen. You can then select individual photos and video OR choose to import them all.
This would certainly be a handy way to share video and photos between devices at school or in other settings!