animating Photoshop images in Flash

Adobe has a great tutorial on how to import a Photoshop image and layers into
Flash but I haven't found anything to take me the next step. I'm creating a
header/banner for a website and I want 4 separate images to slide in from each
side. From reading the Flash Classroom in a Book, I can't tell if it's better
to use motion tweens or a movie clip or maybe another option. I don't need
detailed directions, just point me down the right path. This website
http://www.exploresaintlouis.com/ gives an example of what I'm trying to
recreate.

mek113