Developer website: j-go
Study, with stroke order diagrams for all Kana and Kanji. Play, K-Snap and KandTiles will help you to remember what you have learnt. PrintShop, easily print you own double sided Japanese flash cards. Just select which characters you would like and choose how many flash cards you would like on each sheet of paper/card and print.
This initial release of K-Snap includes all JLPT level 4 kanji. JLPT level 3 kanji will be included in December'07 and more will be added early in 2008. All will be free updates to registered users.
*Previously available here