Spacecraft Propulsion

http://en.wikipedia.org/wiki/Spacecraft_propulsion
http://www.sciencedaily.com/articles/s/spacecraft_propulsion.htm
http://www.space.com/21337-advanced-spacecraft-propulsion-concepts-images.html
http://www.angelfire.com/co/rwrwrw/prop01.html
http://science.howstuffworks.com/electromagnetic-propulsion.htm

Videos
http://www.youtube.com/channel/HC_9Dyfm8iVj4