Obama to pay college students $40/hr to volunteer

Taken from http://change.gov/americaserves/:
“all college students who conduct 100 hours of community service receive a universal and fully refundable tax credit ensuring that the first $4,000 of their college education is completely free.”

Well, students won’t really be paid $40/hr, technically it is a refund of their own money back to them…

What constitutes a “college student”? How will the exact amount to be refunded be tracked?