Flashcards allows users to create their own cards. Users can also insert images and download card decks.
AnkiDroid lets you create flashcards in the app or on your computer using Anki, and you can then transfer them to your mobile device. Over 6000 already created decks are available and it also syncs with AnkiWeb.
Flashcards Helper (Android)
Flashcards Helper allows users to create their own cards, and is able to sync and share cards. Users can create cards on their computer and sync with the app.
iFlash Touch (iOS)
iFlash allows users to sync decks of flashcards from their computer to their iPhone, and back again, over a wireless LAN.