This reminds me of the commenting system that I think all the Gawker blogs use. There is a live preview directly above the comment field that shows exactly how the post is going to display on the page. A lot of forums do the same type of thing, but not live.

My brother has the same problem though, he can read and re-read right through his mistakes and never catch them unless they are pointed out to him. He's not dumb or illiterate, but I've always thought that he's mildly dyslexic.