We get many questions regarding the specifications for page layout on our books. The short and sweet answer is your working canvas should be set to the size of the book at 300 DPI in sRGB.
For instance, if you were laying out an 8x10 book, you'd start with a canvas that was 8 inches wide, by 10 inches tall at 300 dpi. The only book size that is not exactly the right size is the 9x6, which is actually 8.5x6.

What about the trimming on the edges? We do trim about 1/16 of an inch off the outside edges, and between 1/16th and an 1/8th of an inch on the books with the hand torn edges. You'll still want to setup your pages exactly the same way, but just be aware that the edges will be trimmed a hair.
By the way, the full bleed pages look fantastic with the hand torn edges! See below:

What about double page spreads, or panoramic images? You can absolutely setup a double page spread with images going across the middle. The only tricky part about pano pages is they need to be split into the left page and the right page before uploading. The way I layout my books is I start with a double page canvas, layout all of my pages, and then on the last step, I crop it to split it into the left side and right side.
There is basically no center gutter to worry about in the design either. There is a fold, as you can see in the picture above, so I wouldn't run text across the middle or put the brides head there, but you can definitely run a full image through the center.
Back to our 8x10 example, for a double page spread, we'd start with a 16x10 page, create the layout and then split it into the 8x10 sides. Those of you more savvy with Photoshop can probably whip up an action to batch process all of those spreads into the sides, thus saving a bunch of time.
Hope that helps and happy designing!