Sometimes I can't find in Google a term seemingly obvious and popular, as bash shell tricks (look for Bash Wiki). In such case blogosphere and news groups help me. Recently I couldn't find good GIMP tutorial on YouTube. After some attempts at the end I hit malgalin 's YouTube home page (a British teacher :-)) with many tutorials easy to understand and inspirational. Another interesting thing there is that he is very attentive when he uses others' resources - he pay really big attention to what he uses and what permissions are on that resources.
Malgalin created 4-parts path tutorial inspired by very impressive "show" of rafz000 from Brazil: