Web-based Flash Cards

A request came in from a teacher asking if I knew of any programs available to make review/study cards.  This teacher wants to use the study cards as a review tool that could possibly be shared amongst the students.  They thought of using PowerPoint but wanted to know if there was anything else out there other than the traditional pen and paper method.

First of all, for those of you out there using the traditional pen and paper method...there is nothing wrong with traditional :-).  My first response to this request was to use the "Notebook" software for the SMARTBoard, although this specific teacher does not have a SMARTBoard.  Not really knowing what was available, I did what most "not knowing" people do...Google.  My search came up with some wonderful results which I discuss and provide links below.

1. Flashcard Machine - A free web application enabling users to create interactive web-based flash cards and share them with others.
   
2. Cramberry - A free web application allowing users to create simple flash cards in an easy to use, clean interface.  Appears to have an app for the iPhone/iPod touch.
   
3. FlashcardExchange - A free web application where you can create, study, print and download flashcards.  Some features include creating flashcards in different languages, sharing flashcards over the Internet, creating flashcards with images (jpeg), creating audio flashcards (mp3).