This is a fantastic article I found this morning.  These are just a few excerpts, so be sure to read the entire article.

"There is something unsettling and very familiar in the Obama poster campaign which has plastered his image over the country. The posters depict the same graphic closeup of the candidate with one block word either "Hope," "Change" or "Progress" at the bottom. I knew that I had seen this before, and then it came to me that this image appropriates the graphic style of totalitarian Soviet propaganda."

"Coincidentally or not, the website for the artist, Shepard Fairey, who designed Obama's posters is called Obey and boasts on its homepage, "Manufacturing quality dissent since 1989," and the artist bills himself as an agent of "worldwide propaganda delivery."