I finally did it, I just couldn't keep with my pocket PC anymore and got the iPhone. unfortunately my Japanese studying just ground to a halt.
Please, Please, Please, make an iphone version. Stackz is truly superior to the other flash card apps out there (lingvosoft and declan) I'm sure the exposure that the itunes application store can give you would be enough to make this app the standard.
iStackz has been released recently to the app store!
Find it here:
https://www.stackz.com/home/shop/