OpenCards is a flashcard learning extension for OpenOffice Impress.It is completely free and open-source software.The  Lastest version  OpenCards 0.16 was released on 23-7-2008.

Feature:

… is easy to use: Just create flashcards as you’re used to create Impress-slides
… is well supported: There are already millions of freely available flashcard-sets
… allows to learn any Impress/Powerpoint-file as flashcard-set without conversion
… runs on every major operating system and is free and OpenSource
… will reduce your memorization efforts by implementing state-of-the-art methods for spaced repetition

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Download OpenCards 0.16

Video Tutorial:
OpenCards tutorial (only part 1 :(  )