Fill a 1-gallon pot half full with water and bring to a boil over high heat.
Add corn and boil for 7 minutes or until kernels are tender.
Drain corn.
In a small bowl, combine melted margarine and garlic salt.
Using a pastry brush, coat corn with margarine mixture.
Place in serving dish and lay 1/2 slice of cheese over each ear of corn.
Allow to stand for 5 minutes before serving so that cheese melts