Word for someone who thinks they can do anything, and believes everything they do is right but others are wrong

If someone thinks they are always doing the right thing, and believes others are wrong, what would I call them?

Say, for example, I did something that person considers wrong. But then on another occasion, the same person does the same thing I did and believes they are right. So they feel like they're an exception, but at the same time, others are wrong and can't act like that.

self-righteous

confident of one's own righteousness, esp. when smugly moralistic and intolerant of the opinions and behavior of others.

Also from Wikipedia:

Self-righteousness (also called sanctimoniousness, sententiousness, and holier-than-thou attitudes) is a feeling or display of (usually smug) moral superiority derived from a sense that one's beliefs, actions, or affiliations are of greater virtue than those of the average person.

Self-righteous individuals are often intolerant of the opinions and behaviors of others.

Also pharisaical fits to your example:

Someone who is pharisaical preaches one thing and then does another — not a good trait for politicians or even playground pals.

Why use pharisaical when you could say hypocritical? In general, you would probably use the word in especially severe cases of hypocrisy, particularly when someone is not only a hypocrite, but acts superior and is being particularly annoying about it.

Consider the definition found in the American Heritage Dictionary of the English Language, found online at education.yahoo.com for the term know-it-all

One who claims to know everything and rejects advice or information from others.