Cell-phone texting has become the preferred channel of basic communication between teens and their friends, and cell calling is a close second. Some 75% of 12-17 year-olds now own cell phones, up from 45% in 2004. Those phones have become indispensable tools in teen communication patterns. Fully 72% of all teens – or 88% of teen cell phone users — are text-messagers. That is a sharp rise from the 51% of teens who were texters in 2006. More than half of teens (54%) are daily texters.

http://www.pewinternet.org/Reports/2010/Teens-and-Mobile-Phones.aspx?r=1