Tara, whose name means star, embodies the sacred feminine energy found in all of us. Viewed like a brilliant light shining in the darkness, Tara is the female compliment of Chenresig, the Buddha of Love and compassion. Tara is the all-encompassing, nurturing mother figure.
Green Tara is often depicted with one leg out of the lotus position, extended down for a quick and decisive response when needed. Green Tara acts swiftly - like a lioness protecting her cubs.
They say in Tibet, that if you learn just one thing in Tibetan, it should be how to get her attention quickly by calling out...
http://www.sukhi.com/tara.htm
OM stands for the goal and TARE TUTTURE TURE the path.
TUTTURE : dispelling all fears. "Fears" is the translation of the Tibetan word used here – the main fear dispelled is that of the delusions.
TURE: she who grants all success.
SOHA. Each word of the mantra – from OM to SOHA – performs the functions explained above; each brings incredible benefit.
http://www.medicinebuddha.org/tara.htm
The final word SOHA means establishing the root of the path within your heart. In other words, by taking refuge in Tara and doing Tara practice, you receive the blessings of Tara in your own heart. This gives you space to establish the root of the path, signified by TARE TUTTARE TURE, in your heart. By establishing the path of the three capable beings within your heart, you purify all impurities of your body, speech and mind, and achieve Tara's pure vajra holy body, holy speech and holy mind, which are signified by OM. Your body, speech and mind are transformed into Tara's holy body, holy speech and holy mind. This is the rough meaning of OM TARE TUTTARE TURE SOHA.
Tara is in the nature of green light, with one face and two arms. Her face is very peaceful, with a slight smile. Her hair is very dark, half tied up and half loose, and decorated with an utpala flower at the crown. Tara is adorned with jewel ornaments of necklace, bracelets, armlets, anklets, and so on. Her eyes, very loving and compassionate, are not opened widely but are fine and a little rounded. Tara's eyes express compassion for you, like the look of loving kindness a mother gives her beloved only child. Tara's right hand, holding the stem of an utpala flower, is in the mudra of granting sublime realizations. Her left hand holds the stem of another utpala flower, with three fingers standing upright to signify refuge in Buddha, Dharma and Sangha.
http://www.fpmt.org/teachings/lzr/tara.asp