Here is the how-to for the accordion book I made Kristin for Valentine's Day:
Here are the book and cover templates. They are both in pdf form so you will need to open them in Illustrator to edit them.
Come up with something original to say to your loved one.
There are 16 spots to fill so be imaginative and try to tell a story.
Select some photos that you want in the book. You will need 14 images, as two of the spots on this side will be blank.
Figure out what paper you want to print on. I printed on an ivory sheet of Canson art paper and it worked very nicely (even though it is not intended for inkjet printing). Note that whatever paper you use must be printable on both sides.
I originally wanted the book to be bigger but ended up scaling it to 75% when printing. (I was very happy with the size: not too big, not too small). I have the luxury of printing on a large format inkjet printer at work so I was able to print on a 20" x 25" sheet. If you don't have this capability, you can always scale the file down to fit on an 11" x 17" card stock. I based the envelope template off the 75% scale so if you are able to print this big, I would. If not, you can scale the envelope to fit whatever size you end up scaling the book to.
Print both sides of the book (at the desired scale). Cut, score and fold where indicated. Refer to the image of the unfolded book to see which way to fold each page. The blank left corner page on the image side gets cut off completely as this is the page that goes on the right inside cover (the opposite side should have the text you want on the inside cover). The other blank page on this side is what gets adhered to the left inside cover.
I highly recommend making mock-ups on cheap laser paper until you have it exactly right. Printing double sided with scores and fold can be a nightmare—and my templates should smooth the process out—but there will inevitably be kinks that you will have to work through.
Choose a heavy cover stock for the cover.
Once you have printed, scored and folded, measure the book and scale the envelope template so that there will be about 1/8" around the edge of the paper once it is mounted to the cover.
Print the cover template and cut, score and fold where indicated.
Place the book inside to see if it fits nicely. There should be about an 1/8" around each side of the pages to be mounted in. Trim top and bottom evenly if too tall
Stick the single page to the right side of the inside cover using twin-tack, spraymount or something similar. Do the same for the blank page of the accordion. Now you are almost done.
If you want to do a cover with hardware like mine, you can punch a hole 3/8" from the tip of the cover flap and hammer a grommet in. You will need to have don the same with the hardware on the inside left cover before you mount the accordion in (should be placed 3/4" from the left hand side of the cover). (You can always go the easy route and place a dot of velcro under the tip of the cover flap (I have done this with other books and it works fine). Tie a string through the grommet and wrap around the hardware to close the book.
Give to that special someone for any occasion.