There are many ways in downloading video files in youtube its either you use a software or download it manually through site that is not needed a software to download a video. Fo the software I used the IDM to download a videos from youtube through this software you can easily download youtube vidoes but not only youtube videos but also in any other site because once the IDM can detect a video the IDM will appear near to the screen of the video and state that download this video and click it. Then after you download go to the corresponding folder of the video you download.
In the manual download through online site just go to http://www.keepvid.com and once you are there in the site you will see a rectangular box. Go to youtube.com and search for the video that you want to download, after that if just copy the URl link or the address bar link and then go to keepvid.com, paste the URL that you copy from the youtube and click enter. Wait until it finish loading, After loading you can now see the download link just click to your choice if you want an FLV file, MP4 or 3gp file. Tha’ts all enjoy downloading!!!