Hollywood location meister Harry Medved, co-author of Hollywood Escapes, has a piece on MSN about the locations used in this year's Oscar-nominated movies. If the beach in Letters from Iwo Jima looked familiar, that's because it was Leo Carrillo State Beach north of Malibu, also the location of the nighttime campfire scene in Pirates of the Caribbean and all of the Gidget movies. The combat scenes from Letters were filmed mostly at the Pisgah Crater in the Mojave Desert and in the Calico Mountains near Barstow, Medved says. In Little Miss Sunshine, the "Redondo Beach" scenes actually took place in the city of Ventura and the cross-country drive was shot along the Antelope Valley Freeway and Pearblossom Highway.
Edited to clean up clunky phrasing