Libertarian socialists try to achieve a socialist model of living not through legislating it and imposing it through the state bureaucracy but instead by encouraging people to directly organize to liberate themselves as well as emphasizing education to further organization, cooperation, and understanding in an attempt to emancipate the people from exploitation caused by the concentration of wealth-making capital (resources and the means of production) into the hands of a relatively small number of people, the rulers and capitalists at the top. As a result, these socialists are not traditional reformist state socialists who advocate winning power in pre-existing concentrated decision-making structures (the state), and they have even less in common with socialists who may exhibit more authoritarian tendencies.
Some have dubbed it "voluntary socialism" or "laissez-faire socialism" in that people are allowed to choose to participate. A choice is given to the individual. This may not necessarily be true with state socialists (be they authoritarian or democratic) as participation in that case can be compulsory regardless of what the individual thinks. Those who wish not to participate should be allowed to leave and be left alone. Forcing them to particpate would only cause friction and reduce the productivity of those who do wish to participate in such an economic relationship as they would act as dead weight and ultimately harm the well-being of all involved.
If several individuals come together and pledge to support and protect one another using the skills and whatever else they have for the mutual survival of all involved, that, basically, is an example of libertarian socialism, as there was no state to coerce or force the individuals to come together.
Perhaps the most well-known example of a libertarian socialist in the US today is Noam Chomsky. He's an anarcho-syndicalist, a branch found within the libertarian socialist school of thought. (There are several branches as well as those who don't consider themselves belonging to any branch) George Orwell was also a form of libertarian socialist, as well as Franz Kafka. Emma Goldman was another notable American libsocialist.
The history of those who fought for libertarian socialism has been long and bloody if not painful, but it's the history of struggle in general.
http://flag.blackened.net/liberty/libsoc.htmlhttp://en.wikipedia.org/wiki/Libertarian_socialism