OK, now I've got a big question for you. I'm working on a site where I installed PS months ago but only used the backend to allow the customer to enter data on the courses they offer. I did a lot of monkey business to give them a front end that displayed the courses but didn't give them ecommerce. You can see what I did here
courses.php and here
courses_category.php?CategoryID=8 and here
So the next step was to finish configuring PowerStore and skin it to match their site. They're not happy with the progress I've made with that because it looks "too commercial".
They had been very happy with how things were looking and don't want it to change. So I could just put some register now buttons on the current pages and only have people entering PowerStore proper at checkout.