I've made flag books for birthday books and given them as gifts.
It probably helps that my DH does DTP and was able to design a template which I have saved, but you could always rule lines and stamp the month?
Anyway, here's a link to a tutorial
http://www.scrapbook-crazy.com/flag-book.html.
I don't think I have pictures of mine uploaded anywhere, but I do have a couple on the PC.