I recently discovered a fantastic blog: Sew a straight line. Apart from having articles and tutorials for every tastes, the best of all is a section called "Sewing Lessons". In this section you can find step by step explanation of different sewing techniques, as do all kinds of pockets, collars ... also talks about interlinings and some other things very useful for sewing.
Perfect for those who, like me, Know a little sewing and are self-taught.
This is the direct link: http://www.sewastraightline.com/2007/08/index-of-sewing-lessons.html