We have a program in WA called Running Start. It allows highschool Jrs and Srs who have passed a college placement test to take classes at colleges and provides free tuition for two years. The credit you take is applicable towards highschool graduation and your associates degree. I did it, and graduated from HS and completed my AA at the same time. According to the wikipedia (I realize not the most reliable source, but the regular website doesn't have numbers) 8% of community college students in WA are Running Start students.
Could this not be implemented on a national level? What better way to encourage motivated, college bound students that a higher education is attainable to them?