As I said in a previous thread, I use several softwares on my Palm Pilot to study japanese. PAdict is a wonderful suite, including dictionary, japanese input recognition (you can draw hiraganas/katakanas/kanjis), kanji dictionary (# of strokes, on/kun readings, stroke order diagram, etc.), multi-radical kanji searches, a simple (and constantly improving) trainer, and maybe even more that I'm not remembering at this time of the night.
Oh, and one of the best features: it's free! (as both in beer and speech)
Oh, and one of the best features: it's free! (as both in beer and speech)