Robotaposter has an extensive archive of Polish posters. It is well worth spending time at their site.
"We are a fresh online poster gallery dedicated to world famous polish poster art. Please spend some time visiting our website and enjoy some cutting edge movie posters by renowned polish artists. Our gallery intends to promote 'the golden age' of polish poster art dated 1955-1965, a very special time when new and revolutionary ideas penetrated this particular field of graphic design."