Place ham on a rack in a shallow roasting pan. Score surface of ham, making diamond shapes 1/2 in. deep. Set aside 2 Tbsp beer, Pour remaining beer over ham. Bake, uncovered, at 350 for 1 hour.In a sm.bowl, mix brown sugar, vinegar, mustard, & reserved beer; spread over ham. Bake 40-45 min. longer or until a meat thermometer reads 140 degrees, basting occasionally.