Reduson.com

Downie may seem like a simple drag-and-drop app-and it is and isn't at the same time! It is designed to be simple to use-just drag and drop a link onto Downie and it will download the video on that site. It isn't simply another YouTube-downloader: Downie supports at this moment over 160 different sites! The full list may be viewed in Downie's preferences, under the Sites tab.
Key features:
Supports many sites-currently supports over 160 different sites (including YouTube, Vimeo, etc.) and the number is rapidly growing.
Postprocessing-need your video in MP4 for iTunes? Or want just the audio track? No problem, Downie can handle this for you automatically!
Quick support-I respond to emails usually within 24 hours and often add support for requested sites in the next update.
Fast updates-Downie is updated about once a week with new features, sites supported, etc.

Here's a few tips for using Downie:
To start, you can drag a link from any browser either on Downie's window, or the icon in the Dock.
If you have more links, or links within some text, just drop the whole thing onto Downie-it will scan the text for links.
You can use copy and paste as well-just press Command-O in Downie and you can insert all the links in the world!