Here's what we know:
* The anime aired in Japan from April 2006 to September 2006.
* It has been licensed for English release in the past by Funimation. However, they are no longer releasing it due to licensing issues.
* Currently, there is no other company that has announced plans to pick up the license.
It's difficult to speculate when or if it will be released in English. The anime's popularity has remained high, and there is a strong demand for it in the English-speaking world. It's possible that a new company might eventually acquire the rights, but there is no concrete information available at this time.