This appears to be a very nice vocab/flash card app geared towards teachers, but useful to students as well, but it's technically not shareware. This is a demo version of a commercial application (though admittedly, the limitations of this demo are very minor, and for the most part, the demo would suffice for general users.)

The price a(approx $40) is a bit high for students looking for simple flash card app, but I imagine it's competitively low as far as comparable software for teachers.