Place ham in 3 1/2 to 5-quart slow cooker. Drain pineapple liquid from can into slow cooker; refrigerate pineapple. In small bowl, combine brown sugar, 1 tablespoon of the marmalade and mustard; mix well. Spread over ham.
Cover; cook on Low setting for 6 to 8 hours.
About 5 minutes before serving, remove ham from slow cooker; place on cutting board. Cut off enough ham to make 2 cups cubed; cover and refrigerate for Ham and Broccoli Soup p.29. Cover remaining ham to keep warm.
In small microwave-safe bowl, combine pineapple and remaining 2 tablespoons orange marmalade; mix well. Microwave on High for 1 1/4 to 1 1/2 minutes or until thoroughly heated, stirring once halfway through cooking. Cut ham into slices. Serve ham with pineapple mixture.