How can i have a product under multiple categories

1. Select edit your shopping cart
2. Select the products tab from the top tabs
3. Choose the product you wish to appear in different categories\
4. Then on the right under "tool tips" select "Classify your product / Select Categories" from the list of options
5. Add the catagories you would like this product to be associated with.
6. Save

A product can exist in up to 8 categories. If you require it in more, then you will need a duplicate category.