David Messner gave a talk on Commerce Server 2007 architecture at TechEd 2007 Orlando. I didn't think too much of it when I saw that he had posted his slides to the Commerce Server Team blog because the slides are usually worthless without the actual presenter going through them. I was however pleasantly surprised to find that he had actually put some effort into adapting the slides to a PDF making the content very useful to those us not fortunate enough to be a TechEd Orlando.

Take a gander at the Commerce Server 2007 Architecture PDF on the Commerce Server Team blog. I believe that this is required reading for anybody working with Commerce Server.