All the stuff you see on those pictures are not running on Windows, so you'll need to install a Linux to get much of the gadgets you see there. Ther are a number of different things going on in those pictures, including applications as well as desktop effects (compiz gives you the cube thing).
If I'm not off target, I see a username in one of the applications on that Desktop link you posted, as well as on the desktop: "Shrikant" is the name, and I know there are a number of LQ members who's usernames are "Shrikant-something" so maybe if you search around, and especially look in one of the (very long) threads called "Post your Screenshot" you can find out who's desktop that shows, and they can tell you what they have running, and on which Linux distribution.
Other members will also perhaps be able to identify some of the items & applications on the page, such as the Banshee music player, the Gnome system monitor, etc.
For starters, you'll need to install Linux. It's hard to tell what Linux OS is running there, so hopefully some other members, maybe even the one who owns that desktop, can help out.
Welcome to LQ!