I learned a lot about applying for SSDI from this website:
http://www.thedisabilitydigest.com/
I wanted to have a clue, in case I continued to fail at jobs. I feel like I have gone from clueless, to better than average informed - thanks to this site. Also, when I have been doing really poorly in managing my depression, folks trying to be helpful have said that I could apply and partially solve my problems by doing so. Well-meaning though many of them were, some seemed to have no idea what it takes for an application to be approved. I'm so glad to have an idea.
The site supports itself through advertisement, but I consider the site founder to be running this site with integrity.