I would suggest you start off watching some Walt Disney Movies like Finding Nemo, Toy Story, The Lion King etc. All these movies are generally easy to understand as they are really meant for very young children. I would also recommend the movies 'All About Eve', 'Buffalo 66' and 'Chinatown'. These movies are quite comprehensible. Jack Nicholson speaks very clearly even when he shouts.

When I was learning French, I found that watching French films with French subtitles helped heaps. Try it, my friend: American movies with English subtitles!

An entire generation of American watched "Finding Nemo". Watch it even when the characters are somewhat annoying. Just keep swimming.