I haven't heard any announcements that its been discontinued in the US but it was never really all that popular or easier to find to begin with. From what I've seen of it, the game play is relatively unique, but the game suffered from a number of issues including issues of balance and issues pertaining to the license. By license issues I mean, card games that are based off of licenses (in this case a video game) are limited both in the type of cards they can create (you can only make things that existed within the license) and limited in the sheer amount of content (once you've made a card out of anything meaningful that was in your license the game typically dies). These factors have stifled Kingdom Hearts ability to become particularly popular. It also doesn't help that most people know the game is a port of the japanese card game which already died in Japan a while ago (do to lack of additional content to make cards about).
So again, as far as I know it isn't officially done with, but even so, finding any area that still carries it may be quit difficult.
Also after a little digging I have found that the third set has apparently been delayed (but not yet canceled)
"I regret to inform you that due to unforeseen delays in approvals from our Japanese partner, the third set of the Kingdom Hearts TCG, Light and Darkness will be delayed and will not be coming out in June as planned.
Once we are given the go-ahead, production can begin immediately.
Fantasy Flight Games apologizes for any inconvenience and we will post news concerning Light and Darkness as it becomes available.
From what I've heard the third set is scheduled to release by the end of this month, so if you do know a shop that sold Kingdom Hearts but is currently out they may recieve the third set soon.
Thats all the information I've been able to scrounge up. As much as I did enjoy the kingdom hearts games I really wouldn't suggest investing much money in this game, it definitely seems to be a sinking ship (if it hasn't already unofficially sunk).
The bunnies of Lavato have special abilities, like 'Action Skill: Make Carrot Disappear.'