This tutorial will demonstrate some functionality specific to the Configurable product type. This post complements the overview of this product type, which you can find in my previous posts: Magento Configurable Product Type (Part 1) and Magento Configurable Product Type (Part 2).
I will lead you through developing a simple Magento extension that will make a small change in the way configurable products are presented in the front-end. Normally, when you open a product detail page of a configurable product its options are not selected. Because of this a customer is unable to add the product to cart immediately. We are going to load configurable products with their options already pre-selected. The test shop the extension is developed for runs sample product data, which you can download here.