I found an old archive of Games Workshop with TONS of articles about
40k and regular Warhammer, If it says that the file isnt found then just hit the refresh button a couple times.
This is the Painting and Modelling section.
http://web.archive.org/web/20070911032034/us.games-workshop.com/games/40k/painting/painting.htm
If you don't see the the NEXT and LAST buttons, then look towards the bottom, when your cursor becomes a pointing hand you found it