writes "After it was long rumored and discussed about, the ability to text 911 in case of emergency is slowly rolling out in the United States to subscribers of AT&T, Sprint, T-Mobile and Verizon Wireless. For the time being, the service is available in areas of Colorado, Georgia, Illinois, Indiana, Iowa, Maine, Maryland, Montana, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Texas, Vermont and Virginia. According to the FCC, the service will gradually roll out to more areas and by the end of this year, virtually anyone with a cellphone and enough service will be able to make use of it. Which means that all carriers will support it."
TechCrunch has a deeper article that explains why "you probably can't use it yet
," and links to the FCC's own explanation of the service