"The Mahā Mrtyuñjaya Mantra “is the most famous and oldest chants to Rudra-Shiva. The mantra is attributed to Rishi Vasishta, the most famous of all Vedic Seers (= Rishis). This mantra is the most important Vedic mantra for healing body and mind and for dealing with all negativity and suffering possible in life, whether from other people, wild animals, the forces of nature or spiritual forces. It is a great mantric hymn to Rudra-Shiva as the personification of the Yajna, the Vedic sacrifice, which outwardly is the Karmic movement of the universe, and inwardly is the yogic movement of the transformation of the mind and heart from darkness to light. Reciting this mantra helps us remove negative Karmas in life. This powerful mantra reflects our organic connection with the Supreme. Shiva is present in the beautiful fragrances of our-life experience, the soul essences that we imbibe when we feel things deeply in our hearts. He increases our ability to draw nourishment from both life’s blessing and tragedies. The inner feeding of the soul gradually ripens it over time; then it can naturally leave the field of mortality and enter the realm of immortality, just as a ripe cucumber can fall off the vine without any strain or effort. God realization is found within us, like a seed, as the higher organic potential of the soul...”
– Dr David Frawley

"The Mahā Mrtyuñjaya Mantra "is a potent combination of sounds that, if repeated with faith, dedication and perseverance over a period of time, leads, not only to victory over the fear of death, but eventually to victory over death itself or moksha (liberation). It is therefore known as a ‘moksha mantra’. It is stimulating and heating (unlike the Gayatri mantra, which is soothing and cooling). It bestows longevity, and is designed to cure illness. It wards off evil or negative forces by creating a protective psychic shield around the practitioner. It is said to destroy sorrow and poverty, and to fulfil all of one’s desires. Anyone who wishes to remove obstacles in life and overcome difficult situations or illness should repeat this mantra regularly. If chanted a minimum of eleven times, last thing at night, it will ensure a better sleep and more positive dreams." - Swami Vibhooti Saraswati

Read more of the above at:
http://www.yogamag.net/archives/2007/ajan07/mrit.shtml

Lexis:
tryambakam = the 3-eyed one [epithet of Lord Siva] yajāmahe = invoke, venerate, adore
sugandhim = fragrant;
puṣṭi = thriving, thrive;
vardhanam = he who nourishes life;
urvā = like the cucumber/melon/pumpkin;
bandhanān = bound; captive;
mṛtyoḥmuksiya = liberate from death;
mām = myself;
amṛt = immortality, eternal life

Pronunciation notes:
A horizontal line on top of a vowel (e.g. ā) indicates a long vowel. Long vowels are held for about twice the length than their corresponding short vowels. ā is pronounced like the "a" in "father" or as in "harm". Examples are the words Tathāgata or Padmākara. Here, the lengthening is on ā.

The letter ṛ is counted as a vowel in Sanskrit. The sound of ṛ is a combination of "r" followed by a short "e"-sound, e.g. as in "rich", This is unlike the long “ee” sound in "reef", ‘sheep’, “teach”. An example is the word Amṛta.

A dot underneath means a retroflex sound. In the case of the letters ḷ ṭ ḍ ṇ ṃ ṣ the difference is too subtle, so we can neglect this and pronounce the letter as if there were no dot.

The letter ḥ is an unvoiced breath following a vowel. An example is the syllable āḥ.

The palatal sibilant ś equals a "sh"-sound, like in the word "fresh". Examples words are Śūnyatā, Śāripūtra, or Śākyamuni.

Source: http://www.rigpawiki.org/index.php?title=Pronunciation_of_Sanskrit_words