Browsing this forum, I have seen a lot of anti-leftist statements that reek of ignorance, as well as a blind acceptance of Western "democracy" being a workable system. The truth is, it isn't. The answers to the world's problems require that the people themselves take charge of their affairs, that they establish socialism.
The communist movement may be in poor shape today, but it is still the progressive path. The other political movements attempt to prevent progression or regression, locking us in our current system, lead us back to the past, in some form or another, or are communism under a different name and unaware of the mountain of theory they have at their disposal and their allies across the world.
A socialist state is by definition democratic, which today's Parliamentarian-style "democracies" cannot boast. It will be unable to oppress the people, because everyone is involved, and has a quality education so that they can perform to their full potential. In an ideal socialist state, everyone has equal rewards and lives in comfort, without outstanding needs--the world has more than enough resources to provide for this if they are spent efficiently. Communism is a theoretical state beyond socialism, which will be completely different from our system today and involve people working purely for their own benefit, their needs being provided for by machines owned by a community. It will not be close to our day, though, so it is not relevent to contemporary discussion.
The problem is attaining socialism. Each part relies on the others for its stability, so it is hard to construct it from a system reliant on inequality. It is clear that Soviet-style communism, more accurately Stalinism, will not work. It failed to achieve true socialism every time it was instituted, though the Warsaw Pact countries were arguably more egalitarian and humanitarian places after the Krushchev thaws. This leaves two likely paths--a Trotskyist worldwide "Permanent Revolution" leading all countries to socialism from whatever stage they are in, or a democratic transition remniscient of that Allende backed in Chile.
The problem with a worldwide Trotskyist revolution is setting it up, and making sure that the right people are heading it. A huge amount of dedicated and incorruptable revolutionaries are required in every country, or dictators will be able to easily wrest control of the entire state apparatus as Stalin did from Lenin. Dictatorships are always dedicated toward their own longevity, a behavior nonconducive toward socialism. An exception is the theoretical "dictatorship of the proletariat" which would follow a communist revolution, which, as the bourgeoisie would be dissolved following such a revolution, would end up as a dictatorship of the "everyone" and thusly not a dictatorship at all. The vast scale of preparation beforehand for such a revolution would need to involve millions willing to give their lives to the cause, something very difficult to attain without the resources of a government. A bloodless, pacific revolution would be best, but it is not guarenteed that the state can be overthrown without violation. In addition, the revolution is not guarenteed to succeed, and if the capitalist military is able to crush it another revolution of the same character will not come for many, many years.
The problem with democratic socialism is maintaining the purity of the movement and defending it from being ousted by the right. Parliamentarianism, the form of "democracy" we deal with today, has three main flaws: it moves very slowly, tends toward transient compromises rather than consensus, and gives too much power to those who are in positions of power over those who are not. Because of this, revolutionaries seeking to instate a bloodless revolution through the existing state appratus are pressured to compromise away ideals in exchange for political victories. Also, in most countries the infrastructure of voting is managed with people who have interests in certain outcomes of the elections, very rarely revolutionary. On top of this, in most states the vast majority of a governmen--including the civil service, military, police, and courts--is not directly controlled by popular vote, and is in a position to stage a coup if they do not favor the victors of a major election.
The way to properly achieve socialism is likely in-between these two methods, and the path will be different in different areas. It will also, unfortunately, probably take a long amount of time, and the early revolution will be vulnerable to corruption until capitalists can no longer realistically challenge it. It is unlikely this will ever happen in our lifetime, but like a doctor standing over a dying patient the people familiar with socialism have a moral duty to the rest of humanity to advocate it in whatever way they can.
There is, unfortunately, little concise literature on communism that is not either extremely dated or unreadable without a dictionary of technical economic terms handy. Generally, reading major documents such as the Communist Manifesto and The State and the Revolution over time and looking at articles in current leftist newspapers can provide one with background information and a decent understanding of what communism means. It is also very interesting to look through history, and see how things really went when socialism was almost instituted throughout the twentieth century. The capitalist states try to avoid focusing on workers' movements in their schools, and don't include information that incriminates them in state-approved textbooks.