Wow, I wish I had a nice shelf like that. I have stacks of trades all over my room.
actually if you have the room to do it it's not that hard; I used to have actual shelves, but when we moved I just went up to Lows and bought those brackets for the closets and the mounting bars that you screw to the wall to hook the brackets in. Then I bought 12ft boards and painted them white and set them up there. It was totally cheap, but cost like a third of what buying enough bookshelves to go across the wall would cost - and it holds more b/c it goes all the way across.
(The other thing is that b/c there are brackets every four feet I don't get saggy shelves, that drives my OCD crazy with store bought bookshelves) (Also I bought boards that are only a little deeper than the books so I don't have them sticking out far past the front of the books)