According to St. Alphonsus Liguori, Our Lord revealed to St. Elizabeth of Hungary four special graces that are given to those who are devoted to the dolors of His holy Mother.
(1) That those who before death invoke the Blessed Mother in the name of her sorrows, should obtain true repentance of all their sins.
(2) That He would protect in their tribulations all who remember this devotion, and that He would protect them especially at the hour of death.
(3) That He would impress upon their minds the remembrance of His Passion, and that they should have their reward for it in Heaven.
(4) That He would commit such devout clients to the hands of Mary, so that she might obtain for these souls all the graces she wanted to lavish upon them.
Thanks for the ping, Pyro! I discovered the devotion to the Seven Sorrows during a trip to my local Catholic book store a few years ago when I was still Anglican. I looked at it and thought it was a wonderful way to show rememberance to Mary for her sorrows. It is one of my favorite devotions after the Rosary.
I have a strong devotion to Our Lady of Sorrows.
A couple of sites for you:
A Chapbook of prayers to Our Lady of Sorrows:
And a collection of prayers, poems and meditations I have written on our Lady.