The better the bread, the better the garlic bread. This is one of those dishes you really need to portion control in advance of making it[ because it's just that tempting to overeat. I usually use a half of a baguette sliced lengthwise for four people.]
Preheat oven broiler to high. In a small bowl, whip together cream cheese and garlic. Spread evenly over cut surface of bread. Sprinkle Parmesan cheese evenly over bread. Put on a cookie sheet, place under broiler and cook until golden and bubbly, about 1 to 2 minutes. Serve immediately.