Nobody really knows who St Anne was.  She is not mentioned in the New Testament, and we must depend on apocryphal literature, chiefly the Gospel of James, which dates back only to the second century.

In this document we are told that Anne, wife of  Joachim, was old and that her prayers for a child been unanswered.  Once as she prayed beneath a laurel tree near her home in Galilee, an angel appeared and said to her, "Anne, the Lord has heard thy prayer and you will conceive and give birth, and your baby shall be spoken of in all the world." Anne replied, "As the Lord my God lives, if I have either a boy or a girl, I will bring it as a gift to the Lord my God; and it shall minister to Him in holy things all the days of its life ".  Shortly after Anne became the mother of the Mary, mother of Jesus.

St. Anne was known about in the East in the 6th century, but it wasn't until the late 12th centuary that the West heard about her.  A shrine at Douai, in northern France, was one of the early centers dedicated to her.  In 1382 her feast (now on 26 July) was extended to the whole Western Church.  She became very popular, especially in France.  Her two most famous shrines are at St. Anne d'Auray in Brittany and at St. Anne-de Beaupre in the province of Quebec.

In the Catholic Church she is patroness of Quebec, Brittany, housewives, women in labor, cabinet-makers, and miners.  Her emblem is a door.  St. Anne has been frequently represented in art; eg Denys Calvaert's Presentation of St. Mary (1540-1619) - seen above.  The name Anne derives from the Hebrew Hannah, meaning "grace".

There's more info at Wikipedia.