Are movie posters considered antiques?

It usually depends on the movie poster in question. If you have a movie poster from 10 years ago, chances are it is not an antique. However, if you have a movie poster from 40 years ago, there is a better chance that it would be considered an antique. It is also dependent on the movie, of course. A trashy film poster would probably be considered Kitsch and scorned by the antique community. 

You bet! Many factors will determine whether your movie poster is valuable: when it was made, how it was made(materials and methods), what movie it was for, how many of them there are and the stars in the movie and also the artist. Some artists work are worth hundred or even a few thousand depending on the poster. If you have such items check with an antique dealer in your area or on-line to see where to go for more information. There are also inexpensive collectibles books available at most book stores. Browse a few and see if they have a section on movie posters.