Present it chunk by chunk? Makes it a pain in the ass to type in, or copy'n'paste from Safari (which, being in a country far far away from my ORA book collection, I have grown to love).
Present the whole program and then talk about it? Do you reproduce the fragments you're talking about? Number lines? (Line numbering loses you valuable columns for code, and anyone who has ever line-broken code for publication knows what a precious resource they are). Bold lines of code in the initial presentation?
So many decisions! Can you remember a book with large code examples where the discussion of the code examples was easy to follow? Tell me how they did it! If you can only remember books where it didn't work, still tell me!