The Pop Art Movement started in the mid-1950s and ended around the early 1970s. Some notable pop art artists include Andy Warhol, Roy Lichtenstein, and James Rosenquist as well as many others. Pop art is common on billboards and advertisements and celebrates popular culture. It was also commonly used in comics.
Link to my Pop Art Tutorial: http://www.photoshopessentials.com/photo-effects/pop-art/
My Pop Art