In the 20th century there were two great leaders who claimed that to follow an unjust law was tantamount to immoral behavior - Gandhi and MLK. Each of these men broke laws to demonstrate their disagreement with unjust laws, discrimination, and unequal treatment under the law.
Both of them offer a number of anecdotal examples of breaking laws to inspire moral behavior. History has vindicated their actions.
Yes, I think that social norms, rules, and even laws should be broken if we do not think they are right. A person needs to answer to a higher power. We need to follow our conscience. We cannot just act as others expect us to. We have to take a stand.
In Huck's case, we realize that of course it's alright to break the law in order to help Jim, in fact, it is the morally correct thing to do. However, what you need to realize in this situation is that the world that Huck lived in, 1830s Missouri, did NOT believe that freeing a slave would be ethical. In fact, Huck is afraid of going to hell because he chooses to help his friend. It is an easy thing to read this book now, in 2008, and say, yes, Huck made the correct choice, but Huck not only thought that he was risking getting in trouble, but that he was risking his eternal soul. Having been brought up in a religious society where slavery is believed to be the natural way of things, and where it is considered fine and correct, Huck was damned according to those standards. Now that was really a meaningful choice Huck made - to break a law, to risk his very soul, in order to follow what his heart told him was right.
I think Linda certainly hit on the importance of this topic. This all depends on where your conscience sits with the idea of our democratic, law making society. If you believe that the way our laws are made and enforced is reasonable and just, then it's difficult to argue that any laws are up to interpretation and "ok" to break. If, however, you disagree with how laws are formed, then you're pretty much free to pick and choose what you want to do. Of course, this will set you up for the old argument about which laws should be followed and which shouldn't (stealing bread vs. killing someone).
With that said, I'm a believer that I was raised with strong personal morals and values as well as the inherent American pride that we're all "supposed" to have. I would have a hard time breaking any law, even those I don't view as correct. If everyone had the same idea of conscience, you wouldn't have to steal that bread for your starving family; it would be given to you by someone who either sympathizes or empathizes. Ideal?...yep...but that's the happy place I choose to live in!
It's an old question that has been asked in probably every Ethics 101 class. A variation is if you had no money, but your child was starving to death, would you steal a loaf of bread? Would it be a crime? Yes. Would you have to suffer the consequences if caught? Yes. So should you do it? Yes.
Some laws, such as those having to do with slavery and runaway slaves, are immoral. (Around this time of year, people a lot of people think the law that we have to pay taxes is immoral!) Does that mean these laws are ok to break? It depends. Certainly, we'd say what Huck Finn did was the right thing. Many people were just like Huck before and during the Civil War and helped slaves escape to freedom.
You have to be careful in saying that it is ok to break a law that goes against your conscience, however. What if everybody decided not to pay taxes because it is taking money away from their children? Then what would happen to all the children who depend on government aid, which comes from our taxes? Is it ok to break a law if someone gets hurt by our doing so?