WIDE ANGLE LENS

Hi frds

Now i have a nikon D60 with the basic lens. AF-S DX Zoom-Nikkor 18-55mm, I am planning to go for a wide angle lens. I checked in nikon website regarding the lens. I saw wide angle lenses and other in DX category lens. Wht is the differenc with normal autofocus lens and the DX lenses.

Mainly i am planning to do some landscape photography. Can u guide me on wish lens can i go for my instrument. How abt AF-S DX 12-24mm f/4G .