This is similar to what the Loomis books talk about, but very condensed:

http://www.itchstudios.com/psg/art_tut.htm

I find it pretty useful anyway, and I'm still learning.

As for getting Loomis books online (which I posted in a previous link), saveloomis.org had to remove all the books on the site, but some of the books are still available at fineart.sk (It's probably best to save all the pages to your harddrive)