Some time back I posted here about Impostor Syndrome, which was a recent topic of discussion on Codex, the online writing group I run. That discussion led to my most recent “Brain Hacks for Writers” column on Futurismic, “Wait, you’re not a real writer at all!” which you can read here: http://futurismic.com/2011/09/28/wait-youre-not-a-real-writer-at-all.
You might also enjoy reading Alex J. Kane’s follow-up on the subject on his blog.