1. Shuck the corn.
2. Put corn ears directly on grill racks over med-low heat.
3. Turn a little bit every few minutes, and continue until corn is cooked all the way around and has some lovely brown grill marks.
Yes, you can go through the whole rigamarole of soaking the corn in the husk, grilling it, and then shucking it- but for goodness' sake, why? Who needs burned fingertips? The way I do it, you get a different flavor from the corn because of the caramelization of the sugars; a cross between popcorn and sweet corn. 'tis yummy and easy, the way I like food to be.
Butter if you must, but I don't bother with that either. It's nice to enjoy the simple flavor of fresh, in-season grilled corn.