I came to know this through
a Japanese review.
doubleTwist is a multi-media management system like iTunes, through which you can download/upload/sync your image/audio/video with your cell phone. It supports
a variety of devices.
What I find impressive about this product is that
it transcodes the media files when you download them to your cell phone. Cell phones nowadays are getting more and more like personal computers, but they typically have limitations in which media formats are supported. doubleTwist can make sure that media files you download to your cell phone are playable/viewable there.