I agree totally with Clairewait. I might say that another conflicts of Jacob's is himself and the society that he knows will never accept his true nature. It would be interesting to see how these conflicts compare to others throughout the series.
Internal conflict: he loves Bella but he cannot have her; he loves Bella but she loves his enemy (Edward, and all vampires); he is torn between his love for and protection of Bella and his sheer hatred of the thing that comes between them.
External conflict: The Cullens (and vampires in general): Jacob's family (a wolf pack) externally fights against them and with them (against other more evil vampires).
Jacob's internal conflict would be trying to get Bella to see him as more of a friend. All though he accomplishes that it only leaves him even more heart broken since the love she has for Jacob just are not enough compared to the feelings she has for Edward.
Jacob's external conflict would have to be his constant run in with vampires. In Eclipse he ultimately gets by one and one side of his body becomes shattered. Then there is also the situation about trying to catch Victoria.