Great Expectations-photo

http://www.jvwisdom.com/uploads/images/ladder.gif
The ladder is supposed to signify Pip's experience in society; he recognizes the fact that he has to "climb" up the social ladder to feel significant and worthy. The ladder represents once Pip arrives in London. He is thrust into high society and has difficulty trying to be proper and have manners, which Mr. Pocket kindly helps him correct. The ladder also shows his struggle: at the bottom (working with Joe) he was ashamed of who he was and was constantly striving to be at the top, where he could be respected and appreciated by Ms. Havisham and hopefully for Estella. At this point in the book, Pip would be somewhere in between on the ladder: not yet at the highest point in society but not at the bottom where Joe and Biddy would stand. We've seen Pip develop up to this point with education and manners. Overall, I think the ladder is a metaphor for Pip's struggle in the Victorian society.