Quick pointer for Opacity tweens?

Hi, im a bit of a noob with whole flash thing, mostly a Photoshop and Dreamweaver man…

Im trying to make a simple slide show with 4 images that fade into each other every 5 seconds…Ive got the hang of the motion tweens and can make the images slide about but i want a really subtle fade out and fade in. Is alpha the opacity?

if someone could point out what I need to do that would be great!

Ive got to build a scroller like the one in the below website but with my own images and text for work, how hard do you think it is to do?

may have to get a freelancer to help out…as it sems quite tech?

thanks in advance for your feedback!!