[Rodney]

Or am I noticing a few tshirt online stores with no categories listed and just a one array page of tshirt product?

I think that's because many online t-shirt stores target a specific "niche", so the whole site is one "category" of designs.

When you look at site with multiple categories of designs or a wide range of designs (choiceshirts, t-shirtking, cafepress premium stores), you will normally see a navigation menu down the left hand side that shows the different subject categories.

. Just how many categories of tshirt can you have? eg Humour, Political, Sport etc

As many as you need I wouldn't go into to many "sub-categories" though because then you are creating too many "clicks" to make the customer complete the sale.

Each click is a critical buying decision that the customer has to make. Too many clicks and that decision might not go in your favor

2. If so I wonder how differently and more interestingly it could be listed on a website.. the smart thing is to list it on the homepage, and have the categories accessable from any webpage the customer goes to on your website, and where on the page to put them?

I think this is where useability and customer expectations can play a factor. Customers may normally expect a navigation menu to be down the left hand side. If you get too "cute" with it, you may confuse the customer and have it backfire.

I definitely think if you have a bunch of categories, they should be available from EVERY page of your site to help your site remain easy to navigate. I think a customer should be able to reach any page of your site from any other page of your site (at least that's just my philospohy). Mainly because with search engines becoming more advanced, many times customers will enter into your site from DEEP within your site and may never see your homepage.

. It also depends just how many designs of tshirts you have, I assume those who could print-on-demand could list a heck of a lot more than someone who prints up the stock before hand ready to ship incase a customer buys

I'm not sure if it's a matter of print-on-demand vs stocked pre-printed designs when it comes to a number the number of categories you need. I think it depends on what type of t-shirt site you have.

If you have a few categories, it might work to display them across the top (Mens/Womens/Children). However, if you have like a dozen different subject categories, it probably would make more sense to display them down the side (fishing, humor, dogs, cats, birds, sports, etc)

If all you sell is fishing shirts, then there is no real need for categories (you could maybe just list every t-shirt design in a left hand navigation menu to make it easy to go from design to design).

Interesting topic! Any other thoughts?