Blending pregnant belly photos on CS3

[KylieKiwi]

Hi, not sure if this is where I post a photoshop question...but, just wondering if anyone can help me with blending monthly photos of a pregnant belly together?
I have taken 7 side-on shots of a pregnant woman each month, and now I want to either layer them on top of eachother so you can see each month, or present them side by side on a long landscape photo.
I have had a few clients ask if I can present them in this way and I say, yeah, of course....and now I'm not sure where to start.
Any suggestions or a good tutorial that may help?
Thanks!

[aram535]

Your last shot is your lowest layer, mask each one and add it in as a layer on top of the last one. I hope you did it with a nice off-color background so you can pull them out easily.

Mask Techniques (http://www.phong.com/tutorials/mask.tree/)