http://www.mesiti.it/arabic/grammar/lessons/lesson1/writing_and_sounds3.asp.
Read the 2nd heading, "خ ح i.e. "7A2" and "khA2""
In Hebrew:
http://sagavyah.tripod.com/ALEFBET.html.
Click on the letter "Hheth" for pronunciation.
http://en.wikipedia.org/wiki/Heth_(letter).