So here's my two pence worth.
Socialism is a principled attack on eliteism, whether you live in a fuedal order, an oligarchy of gun and drug running crime lords, a dictatorship or (as is common in the first world) Machavellian government and economic oligarchy.
The political classics like Machavelli's the prince etc. would actually be a good place to start or even the liberal offensive against the eliteism of fuedalism (after all Tom Paine's egalitarianism and advocation of progressive taxation would alienate any anarcho-capitalist I know even though he advocates property as a fundamnetal right) because anyone astute enough to look at McD's etc. will see that we've got a whole new set of fuedal lords to contend with.
I wouldnt miss George Orwell's "Homage to Catalonia" though that's a really important text that, after that your on to peoples preferences like if it's straight anarchism check out "anarchism" by Daniel Gurin with a good introduction by Chomsky (possibly the best bit of the book) or a more moderate socialism then Bernard Cricks proclaimations of "liberty, equality, fraternity" in "In Defense of Politics" or Crick's better essay "On Liberty:For Fellow Socialists" in his "Political Thoughts and Polemics" there are a million different churches dedicated to the Marxist religion, I couldnt even begin to give you references there I wasnt impressed by the Communist Manifesto at all, infact I thought it was shit and would steer clear of it altogether.