Art questions? I want to learn simple line drawing, silouette and or figure drawing? Also What type of art is this called?

http://www.allposters.com/-sp/The-Dog-Posters_i323186_.htm
http://www.allposters.com/-sp/Carla-Posters_i2819280_.htm


Is there a website or any good books anyone can recommend to show me how to draw similar to this?
Even though it's simple art I would like to master this.
Serious answers please