I wanted to share a link: http://kan.org/michael/mkp/index.php.
Perhaps this isn't the best paint tutorial site in the world but it is really decently laid out and its GW centric with alot of good basic paint guides and tips. Good refresher if your tabletop quality painter, great for a beginner ... not sure if there is much there for the advanced painter, however there are some good modeling guides (guide to magnetizing a baneblade, etc. etc.). Check it out ... its worth it!