How should ham be prepared?

Hams are either fresh or pre-cooked. Pre-cooked hams--meaning hams that have been baked, cured, or smoked during processing--can be eaten right out of the package. Fresh hams must be cooked before eating. These hams will bear a "safe handling" label.
 
Here are some general guidelines:
 
Both canned hams and cooked, vacuum-packaged hams packaged can be eaten cold, just as they are. Some varieties, including the spiral-cut cooked ham, are best eaten cold. Heating can cause the spiral ham's meat to dry out and its glaze to run.
 
However, unpackaged, cooked ham is potentially contaminated with pathogens and must be cooked to a temperature of 165° F. If you wish to reheat packaged cooked hams, set the oven no lower than 325° F and heat to a temperature of 140°F.
Fresh hams must be cooked to a temperature of 160°F. Set the oven no lower than 325°F. The hams also can be cooked in a microwave oven or other counter-top appliances. Consult a cookbook for specific methods and timing.
 
Source(s):
USDA Fact Sheets "Ham and Food Safety"