When you pull up the shackle this plate with holes in it rises up to the pins. With the key in place, the pins will be lined up with the holes.
Here's the key. It's easily decoded with magnetic field viewing film (that's two pictures there the film has to be right on the key).
And here's an idea for picking. I've taped some of the magnetic viewing film on the spot where the key goes. If you bring a magnet near and shake it about, the pins will rattle around and you can see this on the film. Now, pull on the shackle and one of the pins will bind. Then when you shake the magnet you can see that this pin doesn't rattle. The idea is to start building up a key, getting each pin into a way such that it doesn't bind. The difficulty is that pins that are correctly set (so they'd be in the holes) can only jiggle a tiny bit and this is hard to see on the film. They will look like they're binding unless you have a real keen eye. The viewing film is pretty ghostly so it can be a bit hard to tell what's going on.
Of course if you pick it with some other method like http://www.youtube.com/watch?v=pFY3y8l3qe4 then you can use the viewing film to decode. This film is pretty fun, like $10, and you can even use it to read credit card magstripes.