I don’t know how great ALL free guitar lesson videos are because I have not seen every one on the web. But as far as free sites like youtube and about.com I get a little weary. I mean you can get taught something totally wrong and once you learn a bad habit with guitar it can be difficult to break.
Some tips to help you find good content in what you’re looking for should be a site with a lot of information that covers a lot of different material.
Acoustic covers and tutorials, guitar Lessons, tabs, workshops, guitar information such as repair and reviews too.
On this website I love how straight to the point and easy it is to use, and how cool it is that you can learn a song so fast. The videos are high quality with great angles and clear instruction that you can listen to over and over again. Check it out and let me know what you think.