How to download youtube video?

How to download youtube video?
March 03, 2012

For example, http://www.youtube.com/watch?v=lmWdhx_edF4&feature=related

Replace youtube with voobys, you get http://www.voobys.com/watch?v=lmWdhx_edF4&feature=related

Download the video you want to .
1) if you can not download, you need to login the video.

2)JRE(JAVA) is needed in order to download.

3)click 'Run' after it is prompted. Check the box 'Always trust content from this publisher' to download smoothly.