Pixel art tutorials ?

I followed Salmoneous' tutorial about simple tilesets making but I'd like to learn more about pixel art so I can improve my tileset design skills. Does anyone know a place where I could learn more basis, how to make regular patterns, etc ?

Thanks 

I think Derek Yu's tutorial has been posted before, but that's about making a character.
you could use your preferred search engine to get some more (specifics on pattern making).

Thanks Paula