well, here's the answer :
You can use safefrom.net to do that. just go to youtube website and watch the video. if you want to take the video, just input "ss" word in front of youtube link, for example:
www.ssyoutube.com/watch?v=Xeplwq-p4G8&feature=g-logo-xit
press enter and you just go to savefrom.net website. there is a video resolution and file format you can use it to download the video. if you want to download the HD video, you just click useful tools in menu bar, and install the add ons in your browser.
i have another tips, you can use clip.dj website to download video just like savefrom.net. but it's horrible...
