it depends on how big it is. Boil ham in large pot of water for 60-75 minutes or until tender. Let ham sit on a plate for 15 to 20 minutes before carving.
It depends on whether the ham is fully cooked, or partially cooked. Click (or copy) below for a chart for reference.
http://www.hormel.com/templates/knowledge/knowledge.asp?id=749#timechart