This site by the American Mathematical Society gives an excellent overview of voting and elections.
http://www.ams.org/featurecolumn/archive/voting-introduction.html
This site gives some references to Arrow’s Impossibility Theorem:
http://mathworld.wolfram.com/ArrowsParadox.html
You can use this site to find real-life examples of voting dilemmas:
http://www.archives.gov/
This site has an agenda aimed at proportional representation. Arrow’s impossibility theorem proves that there is no perfect voting method, but this site does make interesting reading.
http://accuratedemocracy.com/elect.htm#Page2