how to create a catalog

Hi, Im building a catalog for a company that has two wordpress sites. I need to make a catalog that has as many fields as i want to add including author, book isbn, etc. I need to have the catalog items able to show up on both sites displaying the info i want to show on each site. I also need to organize the items by category and author.
If anybody has seen anything that has all these features and is free please let me know.
thanks