In 1984, what is the main conflict and is it external or internal?

I agree that Winston's conflicts are both external (man vs society--i.e. the Party) and internal (Winston vs his conscience). The most interesting thing about the internal conflict in this text is that, for most of the book, it is half formed. Winston begins defying the party with only instinct and trace memories to guide him. He doesn't struggle within himself because he doesn't know who he is. For the most part, his struggle with the Party is also half-formed. I think this is part of the point of the novel: Winston does not know who or what the actual opposing force is, so he does not know who or what he should be in conflict with (yes, he understands that he should resist "the Party" and all that it stands for, but he does not know who, precisely, the Party is).