Firefox 3 using SQLite database to store all information of your website history, cookies and form history. Every websites you have visited, forms that you filled-in will be stored in their respective files.
To view these files or any files with SQLite format, use SQLite Manager, an add-on for Mozilla Firefox. The interface of the add-on is simple and not too complex. Just click the Open icon, and choose the SQLite file that you want to view.