Anki

Anki screenshots

Anki is a spaced repetition flashcard program that makes learning easier
Card Browser
Anki 2.0 : Card Browser

Alternative downloads

Vocabilis
Advanced flashcard vocabulary builder.
12.3.0
Fresh Memory
Application for studying languages and other subjects with Spaced Repetition.
1.4.0
Grammar Study Guide - English
Handy preparation guide of english grammar for exams preparation or learners.