Whoa! Much nicer template and very slick looking. I'm probably biased because I love that bluish color
I think my only suggestion at this point would be to use a larger thumbnail at first so a person doesn't have to get several clicks into the site before they see a clear version of the design on the t-shirt (they may decide it's not worth it after a few clicks trying to view the different designs).
Check out bustedtees.com to see what I'm talking about. Your first t-shirt images would work fine without being on the t-shirt. Just a closeup image of JUST the design. Then when you click on it, it could show the image of the design mocked up on the t-shirt with a click to enlarge to show the larger view.
That way, it would be much less clicks for the customer to scan and see all the designs and see which one stands out to them.
100% improvement over the old design though. Great job!
PS. You should also look into the SEO/Search Engine Friendly URL mod or option for oscommerce to make your catalog pages easier to spider for the various search engines.