Well, you are looking at a database that contains a few tables. One of them will be a categories table that will contain categories for items and also possibly to subcategories. Another table will actually be for the items themselves. It would hold all pertinant data for an item, including the category type, and perhaps a second or third category type, in case it fits multiple categories.
As far as displaying data, if you have just a few items to do, you could get by with html's <table> command. If you have more than 5-10 items to list, I'd look into using CSS to lay out a stylesheet for it. Your database will supply the information, PHP will format it, and CSS will display it. That's basically it in a nutshell.
I hope this is what you were looking for...
