I made 2 of them for our 2007 trip. I used black Canson spiral bound artist's pads as the base and then used die cuts and stickers for front/back/title page, etc. On the individual pages, I used random Disney stamps. I was originally planning on doing pages for each character, but I didn't want to contrain who could sign and didn't want to have blank pages if we never saw a particular character. Also, we saw some characters multiple times in different costumes throughout the trip - I think Minnie signed 5 times.
We just got a new book for our next trip and chose another Canson pad/book - green this time - and did the outside all Tinkerbelle themed with chipboard and stickers. I have Cricut die cuts of all the princesses that I will put on the appropriate pages after they sign.
When we return I do 5x7 mini-digital pages w/pics for the facing pages.