A middle school gym teacher inWoodbridge is going to jail for having sex with a teenage student. Craig Yarnall, a teacher at Colonia Middle School, agreed to athree-year prison term in exchange for his guilty plea Thursday. But he could get out after only a few months behind bars. Yarnall also must give up his teacher's license and can neverhold a public job in New Jersey. Police say they found Yarnall in a vehicle with the 17-year-oldstudent in a dark area. Investigators say the two had been havingsex for nearly a year, starting when she was 16.