The Texas Society of Professional Engineers has developed a very good video on the value of your P.E. License.  In all engineering disciplines, the professional engineer (PE) license is one of the most important credentials an engineer can obtain. Ideally the path to licensure begins in the final year of college. This video demonstrates why you should start planning for licensure now.

Although this process may vary from state to state I believe that this video outlines the importance of the license and the preparation needed to achieve it.