You will apply to the individual services for a ROTC scholarship (Army, AF, Navy). The scholarship is awarded by the branch of the military, not the school (as an incoming Freshman).
Look at United States Service Academy Forums for great info on ROTC scholarships. Also, look directly at the Army, AF and Navy ROTC sites.
The first boards have already met and about 10% of the scholarships have been awarded for the coming Fall. These recipients all have very high test scores and lots of EC, Sports and leadership. Most scholarships are awarded in the 2nd and 3rd boards.
Before you consider ROTC an option, you must be willing to serve as a military officer for 4+ years after graduation in a job that the military branch chooses for you.