In order to copy DVD's you need software to "rip" the movie from the DVD to your hard drive. If it is a commercial DVD, you also need to remove the copy protection. There are many, many titles available to do this - on my Mac, I use "Mac The Ripper."
As far as burning is concerned, Toast does a great job on both the PC and Mac.
Authoring and burning are two different functions, and employ different software titles. Authoring is the portion where you make the menus, edit the movie, place the chapter markers, etc. Final Cut , iMovie, and Adobe Premiere allow you to do this.
For burning, I use iDVD for movies I've made; Toast for DVD's I'm duplicating.
<!-- w --><a class="postlink" href="http://www.dvdrhelp.com">www.dvdrhelp.com</a><!-- w --> has a good forum, and loads of information regarding software, hardware and media.
