Just found a really useful guitar site!

I'm not sure if this site has been mentioned before, but I just stumbled upon http://www.wholenote.com . It has a ton of free lessons that I think have been created by users of the site. For each lesson, it even has tabs that you can preview the sound of directly in the browser. And it also has a Groove Builder page which allows you to create simple drum beats and chord progressions to improvise over.

Oh, and I'm not affiliated with the site at all... just wanted to share it with you guys if you didn't know about it already.