The following is the field spec for cart version 3.04 and below. Attached is a sample xls.

1. Category Name
2. Subcategory Name
3. Manufacturer
4. Product Sku
5. Product Name
6. Unit Cost
7. Quantity On Hand
8. Product Description
9. Weight
10. Thumbnail Image
11. Large Image

To upload products and categories navigate to the cart admin menu and click "Import Products".