I think it's either Docky or CairoDock that's been used to replace the standard desktop bars in Gnome. I'm quite happy with the default Gnome look, so I've never tried using either of them myself. Consequently I don't really know much about them.
Your best bet is probably to do a bit of googling about Docky and/or Cairo Dock, then install one of them and have a play!
I don't think you can have both installed at the same time, I think it's a case of having one or the other. But I could be wrong!
That's actually Avant Window Navigator. It's in the repos. Very nice dock.
Ah, I'd never heard of that one before....Nice!
I also noticed from the screenshots you linked to that the standard Gnome top and bottom bars are actually still on the screen, they've just been hidden. This can be done by right clicking on each bar individually (i.e. one at a time) and selecting properties. From here you can check the 'show hide buttons' tab which puts buttons at each end of the bar. Clicking one of the buttons will cause the bar to slide off to that side of the screen, leaving only one button visible. Clicking this will slide the bar back onto the screen!