As cell phones become ubiquitous among students and teachers bring more technology into the classroom, schools are struggling to keep those tools from becoming cyber-distractions. As many as 87 percent of American teens use the Internet, and 78 percent of those use it during school hours, according to a fall 2005 report from the Pew Internet and American Life Project. Add to that the fact that teens frequently use cell phones to send brief text messages to one another, and you’ve got the modern-day equivalent of passing notes in class — with less physical evidence. Because teachers aren’t often well-versed in students’ online and text-message behavior, schools are beginning to train them to know what to look for. They’re also developing policies to put a lid on extracurricular Web-browsing and cell-phone use.