What is the difference in method between French and Italian macarons?
As a macaron fanatic, eating that is, and collector of recipes and cookbooks, I referred to Les Petits Macarons by Kathryn Gordon and Anne E. McBride and to Pierre Hermé Macaron and, you are correct, the difference is the meringue, itself: French, Italian, or Swiss.

The French method produces the correct texture and taste,light and delicate, for the French macaron.

Italian meringue is more stable, using hot sugar syrup instead of dry sugar, but the macaron is much sweeter, some feel too sweet, and it's more difficult to get the macaron to bake properly.   

Macaron can also be made with Swiss meringue, whipping the sugar and egg white over a double boiler, then off heat, although this method is less commonly used.