Libertarian socialism (and there are several different forms of it including guild socialism, syndicalism, anarcho-marxism, etc.) are all based on the idea that the proletariat ought to control their own means of production without intervention from the government (much like right-libertarians, libertarian socialist believe that the state should have little or no control over citizens) and outside of a capitalist or any other hierarchal form of production (for example, many lib-socialists are also against slave and feudal production systems, because they also have hierarchies). Essentially think about lib-socialists as attempting to create a society without hierarchal control, such as one inflicted through a central government or through capitalism; as such this political group attempts to create a more fundamental change in society where all are equal as opposed to their statist counterparts that attempt to promote equality through government intervention. In addition, libertarian socialists put a much greater emphasis on individualism than statist socialist (particularly Leninists and Maoists), who prioritize the collective over the individual).
It is also worth mentioning that Marx's original conceptions of an alternate system to capitalism was much closer to libertarian-socialism than it was to statist socialism. This was particularly made clear when he advocated that in order to achieve human emancipation (a concept he differentiated from political emancipation, which is the granting of rights by a state; which is what statist socialists are more concerned with), individuals need to overcome alienation (alienation is the estrangement of man from himself, his fellow men, his productive process, and the end result of his production that occurs when he has no control over what and how he produces) by taking control back of means of production; radical statist socialists, like Leninist, believe that the state ought to control production, which does not overcome alienation because it simply transfers the control over production from the capitalist (or feudal lord, in a feudal system, and slave owner, in a system of slavery) to the state, where the net result for the worker is that he still does not have control over production, and hence he cannot achieve emancipation.
You will find that right-liberatarians and libertarian-socialists have lots in common. Both put emphasis on individual rights (and both believe these are rights that transcend beyond what a state grants). Both believe in a limited central government(s) (with some of the more radical branches of both movements believing that government should not exist at all). Where they differ, however, is their agreement on the economic system. Right-libertarians believe in private ownership of the means of production through capitalism, whereas libertarian-socialists believe in worker ownership of the means of production (through worker co-operatives, syndicates, guilds, etc.). It should be further noted that a free market plays a major role in right-libertarian's conception of capitalism (intervention in the dynamics of the free market by, say the government or another outside force, has led to the term crony capitalism being used by right-libertarians), whereas attitudes towards the free market differ between various ideological factions of libertarian-socialists (with some libertarian-socialists believing that the free market is sufficient in distributing goods, whereas others prefer alternative distribution systems).