PURPOSE: This phase II trial is studying how well gemcitabine and erlotinib work when given before and after surgery in treating patients with pancreatic cancer that can be removed by surgery. Drugs used in chemotherapy, such as gemcitabine, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Erlotinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Giving gemcitabine and erlotinib before surgery may make the tumor smaller and reduce the amount of normal tissue that needs to be removed. Giving these drugs after surgery may kill any tumor cells that remain after surgery.