How can I tell if a product is in a price book?

How can I tell if a product is in a price book?

I've been trying to create price books for my diff. products but when I go to invoicing my price books never show up.

Please include in the Products: All Products a column that tells me which price book that particular product belongs to... and keep in mind that one product can be in diff. price books based on markup for diff. end consumers!

many many thanks
Dennis
dgd