I would like to know if there is a way to have iPhoto auto add pictures in a certain directory, like in the main Pictures folder, and then organize it by the date style.
You can try using Automator to do this, if you have Tiger. But I would worry that it would mess up your iPhoto because the photos would not be where it thinks they are. iPhoto has a very strange way of organizing photos and if you plan to continue to use it, the best thing to do is just let it do its thing.