Where can one research information on mortgage refinance?

Financial websites such as MSN Money, Smart Money and Market Watch often post articles related to mortgage refinancing on their sites. Also, rate comparison sites such as Bankrate and Lending Tree post taverage national mortgage rates for 15-year and 30-year mortgages daily. Someone can use this site to get an idea of what rates are currently and that will help them decide whether or not they should refinance their mortgage to a lower rate.