Posterwhore has ummm...posters.

Sven Brasch

Dan Stiles

Will Bradley

London Transport Circus and Fairground Posters & Eating Out posters [via Fed by Birds]

Movie Poster Jackpot [not the actual name of the site but appropriate] [[In French]]
If site doesn't come up keep trying.
Here is the url:
http://www.alyon.org/generale/theatre/cinema/affiches_cinema/

Guy Burwell Rock Posters

Polish Posters of Japanese Films

Fifty Years of German [hit] Movie Posters

Vintage Bollywood Posters

Spanish Civil War Posters

Illustrated Posters of the National Theatre

Star Trek Inspirational Posters

Italian Movie Posters & Ads [via Martin Klasch]

Maria Ihnatowicz

Posters...



Polish Jazz Posters

Movie Posters...



Ernst Gallery Silent Film Posters [via Trouble in Paradise]