I never actually saw a life book and I really don't know what other people have done, but I did want to put together something for Emily that tells her story. I wanted it to be something that I could start reading to her and showing her now so that she never remembers not knowing how she came to our family. I've been working on her book for a few months now and finally finished it and ordered it today.
I used my scrap-booking software and created each page using the photos I've taken, plus the photos I received from Emily's former foster parents. I kept the text on a preschool level. When she's older, we'll be able to fill in the details for her as she's ready for more information. I uploaded all the pages to Shutterfly and created a hardcover photo book. I ordered 2 copies: one to keep out and read/look at often and one to keep in her memory box so it stays nice.
Here's a few of the pages from the book.