Washington was the first state to ban text-messaging, with this law back in 2007:

THE LAW

(1) Except as provided in subsection (2) of this section, a person operating a moving motor vehicle who, by means of an electronic wireless communications device, other than a voice-activated global positioning or navigation system that is permanently affixed to the vehicle, sends, reads, or writes a text message, is guilty of a traffic infraction. A person does not send, read, or write a text message when he or she reads, selects, or enters a phone number or name in a wireless communications device for the purpose of making a phone call. [Read the full law here]

– Effective January 1, 2008

Midway through 2008 a second law went into place that prohibited drivers from using a cell phone entirely.

(1) Except as provided in subsection (2) of this section, a person operating a moving motor vehicle while holding a wireless communications device to his or her ear is guilty of a traffic infraction. [Read the full law and here]