If any sufficiently advanced technology is indistinguishable from magic, I've got some language-learning magic for you (via Master of 500 Hats). QuestVisual's Word Lens app for the iPhone allows you to point your iPhone's camera at text and it's automatically translated to another language - in your iPhone's screen right before your very eyes, as if what you're seeing through the camera were actually written in the translated language.
My words don't do it justice. Behold:
Clearly the translations they're using still have a way to go, but they still look generally useful as a quick-draw dictionary. And the implementation is just awesome; it looks like it's matching fonts, colors and even the perspective of the fonts. Wow.
The biggest limitation at this point is that it seems to be only available in Spanish to English and English to Spanish, which is a pity. As I'm currently in Japan, that won't be of much use to me, but I'll keep my eyes peeled for a Japanese-to-English version. (Actually, even an add-furigana-to-kanji version would be pretty darn useful for those odd kanji whose readings I can't remember on the sides of buildings and the like.)
If anyone's actually given this thing a go, please drop a note in the comments and let me know what you thought.