I am an MVC newbie. As far as I can tell:
Perhaps this link will help you better understand the Model. They can play the role of a Data Transfer Object or be more in depth as the link describes. However, they shouldn't be your DAL in my opinion. Many examples I see handle the Business logic & DAL with the service & repository patterns.
Check the MVC Contrib Project and the code camp sample to get an example of this.
I also found Rob Conery's eCommerce Storefront and the Northwind MVC starter kit to help.