There is a difference between anger, and righteous anger. As Jesus got upset when He went into the temple. It was like barn yard, and greed...this is were the gentiles was suppose to worship. The things that anger God should anger us. Murder, rap3, the things we do to each other. If everyone listen to the sermon on the mount, and lived it...the world would be a better place.
Jesus in the 'sermon on the mount' said "blessed are the": merciful, meek and peace makers. These qualities are antithetical to an angry disposition. I don't recall there being any direct teaching in the 'sermon on the mount' on anger, however the qualities I listed seem to have a direct bearing on someone that is continually angry. In Ephesians it says to not let the "sun go down" on our anger and to not let the Devil gain a "foot hold" through anger. Jesus didn't teach that anger was sin per se and in fact displayed it in the temple (of all places!).
I am a Muslim, I know what our Prophet Mohammad teach us to do when angry: 1. Two men abused each other in front of the Prophet Mohammad while we were sitting with him. One of the two abused his companion furiously and his face became red. The Prophet said, "I know a word (sentence) the saying of which will cause him to relax if this man says it. Only if he said, 'I seek refuge with Allah from Satan, the outcast.' " So they said to that (furious) man, "Don't you hear what the Prophet is saying?" He said, "I am not mad." 2. Al-Qass said: We entered upon As-Sa'di. A man spoke to him and made him angry. So he stood and performed ablution; he then returned and performed ablution, and said: My father told me on the authority of my grandfather Atiyyah who reported the Apostle of Allah (peace be upon him) as saying: Anger comes from the devil, the devil was created of fire, and fire is extinguished only with water; so when one of you becomes angry, he should perform ablution. 3. The Apostle of Allah (peace be upon him) said to us: When one of you becomes angry while standing, he should sit down. If the anger leaves him, well and good; otherwise he should lie down. I hope this help :)