[Game website] After weeks of speculation and following the conversion of both the Korea and Japan servers, En Masse Entertainment finally announced that the North America server will be entering the Free-to-Play phase come February 2013, which is next month. No specific date is set thus far. Read the official FAQ here!!!
An additional piece of information, TERA North America has IP block implemented, which is stated here in its FAQ section. For players who are blocked, I am sure that the Europe server is still not blocking anyone.