Virtue ethics is a very weird thing and difficult to define. [If you want to read a good introduction of virtue ethics, I suggest you "virtue ethics" by Rosalind Horsthouse. I'm giving my own thoughts about it.]
In its most extreme form it would be the thesis that every moral and evaluative concept can be reduced to the concept of a good human being, or a good character. I think no real philosopher held something so implausible except maybe Nietzsche, and some contemporary analytical philosophers who thinks themselves as Aristotelians: Geach and Foot.. Do not quote! (Here is why I classify Nietzsche as a virtue ethicist in this sense: a possible interpretation of the first essay of the Genealogy is that the concept of "good" and "bad" person is prior (genetically prior) to both the concept of "good" and "evil" character, and to the concept of the moral good. "Good" is to be understood an attribute of "good people"; that it, the term that people belonging to ruling class - the good, the noble, the strong, the powerful - started to use to refer to themselves. Everything else is said to be good as in relation to this: good acts are those acts that emanate from noble people, good tastes are tastes of noble people, etc...) (If I am right, Geach and Foot's view, which denies that there is a meaning of good different from the attributive sense, seem to imply something like Nietzsche's view. This is all a very personal theory; while what I'm going to say from now on is much less controversial.)
There is a more moderate view of what virtue ethics is, which I think it makes little sense to see in opposition to deontology or consequentialism, even if it differs from the two, especially in terms of approach. The model of this sort of virtue ethics is especially Aristotle. According to this view, the central concept of virtue ethics are the concepts of a good human being, of a virtue, and of eudaimonia or fulfillment, that is, the good life. Virtue ethics differs from the other two approaches primarily (I would say exclusively) in that for virtue ethics the focus of moral theory should not be the evaluation of norms of conduct and actions (taken as atoms of behavior) but the three aforementioned concepts. The difference, therefore, is in what virtue ethics, against both consequentialism and deontology, sees as the business of moral theory and as having a proper understanding of morality.
Let's make an example. It is crucial for the success of both a consequentialist and deontological morality, that they provide some philosophical method to discriminate good and bad actions (or right and wrong, if you prefer), usually (I would say exclusively) conceived as a general rule.
Consequentialism, in fact, is nothing but a class of formally analogous general rules, in the sense above. A rule is consequentialist if it has the following form: action F is good iff its outcome (which may even coincide with the action itself!!!) is good (or better than any other possible outcome, in some versions.) So if you want to ascertain whether a certain action is good your consequentialist instruction manual tells you the following: look at the consequences of the action (which may include the action itself), evaluate their goodness, and if you produced more good than bad, well, boy, you did a good thing. (In some versions, if you did what produced more good than bad than any other action you could have done you did the right thing, otherwise you did the wrong thing.)
Deontology is also a class of formally analogous general rules. A deontological morality may even contain some consequentialist principle, but, on a whole, it will be different from a consequentialist one because it will contain rules forbidding you to do certain actions whatever the consequences in terms of the goodness produced. (So for example, you may not break a promise even if you know that, if you don't, 1000 promises will be broken.) But fundamentally it also consists in providing you with an instruction manual: if you want to ascertain whether a certain action is good or bad (or better, right or wrong) you take your deontological instruction manual, which will contain some list of actions you are not allowed to do, whatever the circumstances. (Some manuals are just a set of rules, like the 10 Commandments. Other, like Kant's cathegorical imperative, consist of one rules from which all other rules can be deduced.)
Now, notice that virtue ethics presents itself as something really different. The virtue ethicist would argue that the proper business of ethics is not to produce instruction manuals. The basic tenet of this sort of virtue ethics are:
1. the Aristotelian idea that rules in ethics obtain only "for the most part"; and that you need experience and a good upbringing to be able to judge the goodness of an action
2. the idea that it is more reasonable to start by evaluating a person's character, and judge her action only on the background of the character it came from.
A virtuous agent will certainly have in mind something like a list of actions that are standardly wrong. I will see the fact that a certain action the breaking of a promise as a good reason not to do it. But the morality of the virtuous agent is far from exhausted by sticking to the rules that forbid breaking a promise, or lying, and we may also conceive of situations in which he will assess the consequence of maintaining a promise or telling the truth and decide that he has reasons not to do it.
A virtuous action therefore takes consequences in great account. But he is not concerned, first and foremost, with the production of the highest quantity of good. A virtuous person is supposed to be able to perceive the moral quality of an act, for example, it's being corageous, charitable, sensitive act, as a reason to do it, and this of course is connected to its consequences (a corageous act is an act done in the presence of danger, in view of a greater good), but there is nothing like a calculation of the overall goodness of the outcome. The attitudes of a virtuous agent could be more similar to those of the adherent to deontology: he will not make an uncharitable act for the sake of increasing the moral perfection of that person's life.
[Consider the difference between the two definitions, or if you want, between Aristotle and Nietzsche. I think so. Aristotle, for example, would have never dreamed of assuming "a good person" as the primitive and only authentic sense of moral goodness. And, in opposition to Nietzsche (in the Genealogy) he has never think of it as a mere (unconscious) reflection of positions into a social hierarchy ("the good" as the best, the noble, the powerful, the ruling class). It is true that he uses the understanding of a good man, that is to say, of a man of his social class, as a method to define the good, or choiceworthy life. But the focus here is on what makes a life choiceworthy. It is true that, for Aristotle, we can discover what is a choiceworthy life only by looking at what sort of life the nobles prefer to live. But I think we can infer from his writings that his reason for doing that is that he is sincerely convinced that such people are better than other men (and of course, incomparably better than woman and slaves) at perceiving the real value of things. In other words, the concept of a good man plays and epistemic, not an ontologically constitutive role.
Notice the difference with Nietzsche. Nietzsche can be read as arguing in the Genealogy that there are no real values, or at least no real moral values (moral values are no values at all); and that moral language should be understood along lines different from the promotion of moral goodness, or happiness. For Nietzsche, when the Greek called an act, or a life, "good", all that they meant by the word "good" as that it was an act that it was typical for a noble man to perform, or the life that it was typical for a noble man to live, or simply that it was an act of a noble person, and the life of a noble man. After the "slave revolt in morality" things changed a bit; which is to say, the noble started to look at themselves, and at their most typical actions, with a sense of guilt. (Which was a psychological reflection of the hate they received from the people of the inferior class.) So "good" - that is, "noble" - was turned into "evil"; and "bad", that is "slavish", was turned into (morally) good.]