This probably warrants being started as a New Thread, since the topic is very different.

Take a look at this tutorial: http://www.zen-cart.com/showthread.p...-your-Products on adding new fields that you can edit in the admin and display in the store

Or, if you want a more "automated" way, test out Numinix "additional product fields" plugin, perhaps on a test copy of your site first.

Either way you'll still have to manually alter your custom storefront template to add the fields to the appropriate "tab" that you said you've got.

If those aren't what you're looking for, then start another thread for discussion about it.