PLAINFIELD, Ind. — The lectures so far have covered topics you might expect in any business seminar or college management course — developing a vision statement, improving communication skills and resolving conflicts. But next week, this unusual leadership program will take on issues that reveal its distinctive flavor: application of Islamic law in America and the role of women in the mosque. At the Plainfield headquarters of the Islamic Society of North America, about a dozen current and aspiring Muslim leaders from around the country have been attending what amounts to summer school for imams. Aside from imams, Muslim religious teachers, the class also includes Muslim student leaders, mosque office workers and Islamic center volunteers.