Why are the western countries attacking Libya?

Ok... Gadaffi is crazy and there's no doubt about it. The UN says that they are trying to save civilians and how do they do it? Killing more civilians. Another funny fact, Mr Nobel peace prize 2009 (Obama) agrees with this offensive which is taking lives of innocent people. What do you think about the intervention of the west in Libya, is it because they want freedom for the pele or another interest?