Daring Fireball has just released a product called Markdown, a plugin that converts plain text to XHTML-compliant code. Their stated goal is that_ "a Markdown-formatted document should be publishable as-is, as plain text, without looking like itï¿½s been marked up with tags or formatting instructions".
I'm not so sure, though. Adding links and such requires the use of special shortened tags that don't really flow semantically with the english text any better than HTML. Also, I don't quite understand why HTML is so hard to read. (Of course, I suspect that that may be because i'm biased from years of working with html...)
Overall, I can't say that I'm all that impressed, or that the benefits are all that great. In my opinion, if you're going to have to learn tags and such anyway, why not head over to W3 Schools and learn the real thing?