As I researched Digitizing Your Photos I consulted with several people who have been experimenting with multiple methods for converting color negatives to positive images. If you want more information on this here are some links.Mark Segal and Todd Shaner have written about their findings on the Luminous Landscape (an excellent web resource). This is a good place to dig if you want more options.
I show some basic SilverFast usage in the book. Here is link to the SilverFast website.
Vuescan can also work with camera files, and has a much more simple interface than SilverFast. You can download a demo version and see how you like it.