It is going to be released in some theatres in the States on October 23rd according to Yahoo Movies.
Even better, Ong Bak III is supposedly in production now too.
Tony Jaa is an amazing martial artist. I loved the original Ong Bak, even though it made little to no sense.
There is an awesome sequence in the Ong Bak II trailer (viewable from the Yahoo Movie link above) where Jaa runs up the front of an elephant, does a back flip and kicks the bejesus out of a bad guy on his way down.