If you notice on our site, we have categories of products: Riffs, DVDs, On Demand Video, and "Goodies" (which includes stickers and whatnot). I did this using the Taxonomy module - you can attach Taxonomy vocabularies to the Product node type, and use that to categorize the products in your store. (Then you can create Views pages, like our Catalog, that pulls products belonging to one category - like "DVDs" - or even one subcategory, like DVDS > Action Movies.

The attributes are done in the attribute administration. When you Edit a product, click the "Attributes" tab. (This has to be done after a product is already created ... which is kind of a pain, because you have to go BACK to the Edit form. Something I'd like the Uberdudes to consider changing, so you can go through a multi-step form to create your product, add Attributes and Features, THEN submit it for publication).

You should look up these modules (Taxonomy and CCK) and read through the forum before you go full-bore into developing your site. I had to spend many days reading up and tinkering, and reading other case use reports, before I was able to fully (or even partially!) understand what these great modules can do. I would create a test site as well, that way you can practice, tweak and experiment before making your content live to the public.