Concept Art

Concept art is a form of illustration where the main goal is to convey a visual representation of a design, idea, and/or mood for use in movies, video games, or comic books before it is put into the final product. This is a relatively new designation popularized by artists working in the automobile and video games industries. This term has been in use since the 1930's by the traditional animation industry who was describing drawn or painted images which illustrate the look, feel, design, colors, etc...of the animated movie to be made. Concept art is also referred to as "visual development" in traditional animation. The term was later adopted by the games industry. These illustrations became necessary for developed visual properties. (frm Wikipedia)

Chkout the link for awesome artworks...
http://conceptart.org/forums/showthread.php?t=78102