Here are your best options:
1. The United States Air Force Academy. Being a junior, it is not too late to get a nomination from the proper authorities. Competition is tough, but getting involved in your community and at school, as well as getting good grades and participating in athletics should get you in. About half of each class goes to flight training. Visit www.academyadmissions.com to find out more.
2. AFROTC. This is a program run at a lot of colleges that commissions you as an officer in the USAF. I'm not sure, but pilot training rates are probably pretty good. Visit www.afrotc.com to check this option out.
3. OTS. This is a program which is basically a boot camp for those who would like to become officers in the United States Air Force. Visit www.airforce.com for more details on this.
Don't forget about your options to fly fighters with the Navy or the Marines!