I recently bought Pizza on the Grill by Elizabeth Karmel and Bob Blumer.
The content is divided into two sections. The Basic Training section explains the technique of cooking a pizza on both gas and charcoal grills. The second section provides tons of recipes for pizzas, from classic pepperoni to exotic ones like Maine Event Lobster and Corn Pizza. Most of these will be too exotic for my tastes, but I was mainly just interested in how to cook pizza on the grill.
First you roll out the dough to a 1/8 to 1/4 inch thick circle or square. Add some oil and lay it directly on the grill and cook using direct heat. Take it out, flip it over onto a peel or baking sheet and add sauce, cheese, and toppings. Then cook using indirect heat. Read the book for the details and lots of tips. If you feel adventurous or just want a new recipe, this book has tons to browse through.
Have you successfully cooked pizza on a grill? My husband is more familiar with our grill, so I may have him give these techniques a try!