Personally, I think Pip is not innocent. However, my teacher says he is. Pip grows up in a society full of stereotypes, and therefore, cannot resist the temptations to fall victim of his "great expectations" and look down at Joe and Magwitch. However, in my opinion, if Joe was the one who got the "great expectations", Joe would not feel ashamed of having Pip and try to distance away from him. Also, looking down at someone who has given him money and risked his life to see him is definitely not innocent.
The point made above that the narration derives from an adult Pip is, indeed, a cogent one. For, the reader must consider the actions of Pip in the context of his age at the time of the actions of the plot. Certainly, then, Pip is an innocent, ingenuous child at the beginning of Great Expectations. However, when he travels to the city, he has a preconceived notion of this benefactor and his "great expectations," a notion entertained enough that Pip becomes snobbish and opinionated and selfish in the Second Stage of the novel. It is not, then, until he is purged of his selfishness through the concern he exhibits for Magwitch, Herbert, and Miss Havisham that Pip regains the decency of character which he has exhibited in the Furst Stage of Great Expectations.
Interesting topic. I agree with jennyrocks in that whatever conclusion you come to, as long as you can back it up with textual evidence, it doesn't really matter, so read the text carefully and think about Pip's guilt or lack of it in his actions.
To me, Pip is more ignorant than culpable for his actions. One aspect of the text you need to be aware of is that it is written in retrospective first person narration, which means that an older, wiser and maturer Pip is writing back looking at his actions. This explains the "two levels" the text often has, for example when Biddy is trying to remonstrate with Pip and the younger Pip thinks she is jealous of his Great Expectations, but the older Pip is well aware of the truth in Biddy's words and the stupidity and ignorance of the younger Pip.
Although the novel presents us with a happy ending of sorts, it is important to realise this only comes about after a "punishing" of Pip, when he is burnt through trying to save Miss Havisham and becomes very ill, and also after he is very hurt through his relationship with Estella. This does suggest that the author feels he does need to pay a price for his actions, though whether he is fully aware of his guilt at that stage is doubtful. It does raise an interesting question though - are we to be held responsible for actions which we are unaware have hurt other people?
You are thinking like a reader. Everyone will always have his/her own opinion of a character's characteristics and moral fortitude. As far as your saying "...looking down at someone who has given him money and risked his life to see him is definitely not innocent." does cause me to believe that you have not finished the story yet. At the end, Pip talks about how he has this unparalleled love for Magwitch and is grateful to know him. He visits him in the hospital and takes care of him.
I have my students form their own opinion about the characters - whether they are innocent or not - based on their observations and textual evidence. If you feel as though Pip isn't innocent, your teacher will be receptive and appreciate your thinking outside the box as long as you back up what you say!