For Japanese language practice for my course I use PocketStackz by some chaps called “Minddate software”. Its an all-purpose language flashcard program with an emphasis on Asian languages (such as that an Asian Unicode font needs to be installed on your PocketPC).
What sets it apart is that you can immediately see what words you need to study at any point since the program sorts the words into “stacks” from “unknown” on the left to “known” on the right. If you get an answer wrong when testing yourself, the word moves towards the left, and visa versa if you get one right. This means when you have only a few hours until a vocab exam, you can quickly refresh the “most unknown” vocab in the quiz.
Vocab or kanji can be tested in pretty much any combination (romaji to kana, kana to kanji etc) and I find I get better results if I use it for short periods of time often. My test results even confirm this – weeks where I’ve spent 5 minutes a day with PocketStackz have seen perfect vocabulary test scores. You still need a drive to study, when when you don’t need to get your textbooks and pen and paper out (or those silly little “word cards”) its easier to find the time.
The software comes with a free PC application so you can make your own lists of vocabulary, but files for many textbooks and series of kanji (including the official joyo kanji) are available on the developers website. I had to make the kanji files for the Genki textbook series since they were not available, but this was painless using the PC software. Top stuff. 5/5.
Plus its only 19$ from Handango and they have a free trial (which I liked so much I bought it). Thats £8!