I'm really into pop-up books at the moment and have bought myself a couple of books to help inspire me to maybe make one of my own. There are some great ones available, including Alice in Wonderland and the Wizard of Oz, both by Robert Sabuda.com who seems to be a bit of a genius - He's managed to create books which are a work of art and absolutely amazing. I
'm trying to find out about one I had as a child - a pop up Bible or Life of jesus type thing. The only thing I really remember about it (I would have been around 3 or 4) was the final pop-up which was a pop-up crucifiction - it sounds gross/crass/hilarious but I assure you it's true
A great list of books to be had at Wonderful World of Pop-Up and Animated Books. keep your eyes out for the work of Ingrid Siliakus who does amazing architecturarl sculptures out of single pieces of card.
Lots of exhibits here, Here, Another virtual exhibition. Interesting stuff about the history of pop-ups.
The Popuplady has a good page with good links, including a link to the world's largest pop-up uterus
Another pop up collection, A very simple How to make page