I'm not sure where you can find it available to purchase, but according to Wikipedia ( http://en.wikipedia.org/wiki/Harry_Potter_in_translation#List_of_authorised_translations_by_language ), the Harry Potter series has been authorized to translate into Latin. Then again, some of the translations are slow in being released, so perhaps it hasn't come out yet.
Yes it's definitely in Latin. All the books have been translated into over 60 different languages and Latin is one of them. I'm sure it's available for purchase somewhere. Did you try amazon.com?? or Ebay?
I have been told that Bloomsbury Publishing has no plans to translate the series into Latin beyond the first two books.
NB: The information is second hand. Also, if people make their voices heard, perhaps the plan would change?
I found one site that sells it, but I think you need to order the *whole* series. (Seven books together.)
http://www.multilingualbooks.com/latin.html
(Scroll down about halfway.)
Latin is a dead language. So no.