Okay, so here's a brief tut to illustrate what I'm talking about with Smart Objects...
You have your back cover and we want to rotate everything within the white metal box so that is follows the box's angle. We could just select all the layers (or group them, or link them) and rotate them, but we do an arbitrary Free Rotate and we don't know exactly how much of an angle we actually rotated the layers, we just "eyeball" it. Then, we decide that we want to add something else, say a caption below a still, or underline the critic quote, or just add some other design element that we now want to rotate at the same angle... the problem is, we just did a Free Rotate and we don't remember the exact rotation or angle. In my experience, it's very difficult to try to adjust another element along the exact same angle as another, I can usually get it close, but if not done right, it can look awkward in your design.
Here's where Smart Objects are great... first off, they remember the transform properties of a layer (scale, rotate, skew, etc. although I don't know if they remember distort or perspective), and they allow the designer to "open" the contents of the layer in a new window for editing (very helpful on my Comic Collection covers, where the back is all on an angle).
Let's give more of an example on how to set it up...
Here's your back cover... let's select the stills, critic quote, and synopsis layers. Go to Layer > Smart Objects > Convert to Smart Object.
[attachment=16845:01.jpg]
In your Layers palette, all of these layers are now condensed into one layer, but you've got a nifty little icon on that layer that indicates that it is a Smart Object.
[attachment=16846:02.jpg]
Now, let's rotate the Smart Object to match the angle of the white metal box (Ctrl-T [PC] or Apple-T [Mac] to begin Transform. You can do this by entering numbers into your Transform toolbar, or by grabbing the bounding box of the layer, but rotate the layer to match the angle of the box. You can see by my setting that the angle is roughly 2.2 degrees (and I scaled the layer down to 95% to get the edges of the box away from the edges of the cover). Another reason Smart Objects rock? If you scale a Smart Object down to 20%, then later decide you liked it better at 95%, you can scale it back up and it won't pixelate - PS remember the full-size data within the Smart Object so you can go back to 100% scale, 0-degree rotations whenever you want... quite handy at times!
Just remember, scaling it above 100% will pixelate the image... those original raster rules still apply. You can't get blood from a stone, and you can't get any larger than the original image resolution without pixelation.
Anyway... here's what your Transform toolbar might look like as you Rotate and Scale the Smart Object...
[attachment=16847:03.jpg]
But wait... now you want to edit the text in the Smart Object... pretend you have a typo or just want to bold the character names or something. Double-click the Smart Object icon on the layer in the Layers palette. You might get a pop-up window reminding you that you must File > Save any changes made to the Smart Object for the changes to take effect. You can choose to Don't Show Again, but I always leave it up as a good reminder (why not?). After hitting OK on the pop-up box, you'll see something like this...
[attachment=16848:04.jpg]
The checkerboard background indicates transparency (although depending on your individual PS Preferences, it might be White, Black, or some other color). I like to leave the checkerboard so that I know what will "drop out" on my actual cover file. Anyway... make your text change (or delete a photo or add something else, whatever...) and Save. Close this window when you're done, you should be taken back to your original cover layer, and you should see that the change you made has applied. In this case, I deleted the stills...
[attachment=16849:05.jpg]
You might be thinking, "I don't need to use Smart Objects, I can remember rotations if I use a simple number like 5 degrees and I can just as easily delete the stills without them being within a Smart Object." You'd be right, but Smart Objects have come in handy a number of times for me, and it's hard to describe their usefulness until you start using them, but they have certainly been a huge help on my covers (the Comic Book Collection, Community, Three Kings, Jennifer's Body, True Blood, etc.) in a variety of ways.
I hope this is enough to get you started and playing around. That's the best way to learn... play around and see what you can do with the new tool. Good luck with it... looking forward to your next update (and maybe a finished cover eventually?).
EDIT: And I second Felipe's idea about grunging up the box a little!
Oh and for those who are wondering my major is Media Arts.