Here's an article I came across the other day...
http://www.catholic.com/thisrock/1990/9007chap.asp
Here are some parts that answers where we are told Biblically or Scripturally, which ever you prefer...that we should pray to Mary...it does not specifically say Mary, but it does say the saints and well, Mary is a saint so...
First, God expects us to pray for one another. We see this in both the Old and New Testaments.
In a dream, God commanded King Abimelech to ask Abraham to intercede for him: "For [Abraham] is a prophet and he will pray for you, so you shall live" (Gen. 20:7). When the Lord is angry with Job's friends because they did not speak rightly about God, he tells them, "Let my servant Job pray for you because I will accept his [prayer], lest I make a terror on you" (Job 42:8).
Paul wrote to the Romans: "I exhort you, brothers, through our Lord Jesus Christ and through the love of the Spirit, to strive with me in prayers to God on my behalf, that I may be delivered from the disobedient in Judaea and that my ministry may be acceptable to the saints in Jerusalem, so that in the joy coming to you through the will of God I may rest with you" (Rom. 15:30-32).
James says: "Therefore confess your sins to one another, and pray for one another, that you may be healed. The prayer of a righteous man has great power in its effects" (James 5:16-17). Thus, according to Scripture, God wants us to pray for one another. This must mean that prayer for one another cannot detract from the role of Jesus Christ as our one mediator with God.
Second, the reason that Christians have the power to pray for one another is that each person who is baptized is made a member of the Body of Christ by virtue of the Holy Spirit's action in baptism (1 Cor. 12:11-13). It is because the Christian belongs to Jesus Christ and is a member of his Body, the Church, that we can make effective prayer.
The reason we pray to the saints is that they are still members of the Body of Christ. Remember, the life which Christ gives is eternal life; therefore, every Christian who has died in Christ is forever a member of the Body of Christ. This is the doctrine which we call the Communion of the Saints. Everyone in Christ, whether living or dead, belongs to the Body of Christ.
From this it follows that a saint in heaven may intercede for other people because he still is a member of the Body of Christ. Because of this membership in Christ, under his headship, the intercession of the saints cannot be a rival to Christ's mediation; it is one with the mediation of Christ, to whom and in whom the saints form one body.
Some Christians--most Protestants, in fact--deny that the Bible gives support for devotion to the saints, but they are incorrect. The Bible encourages Christians to approach the saints in heaven, just as they approach God the Father and Jesus Christ the Lord: "But you have approached Mount Zion, the city of the living God, the heavenly Jerusalem, and myriads of angels, and the assembly and church of the firstborn who have been enrolled in heaven, and God the judge of all, and spirits of righteous ones who have been made perfect, and Jesus, the mediator of a new covenant, and the sprinkled blood which speaks better than that of Abel" (Heb. 12:22-24).
Does the Bible say we should approach the saints with our prayers? Yes, in two places. In Revelation 5:8 John saw the Lamb, Christ Jesus, on a throne in the midst of four beasts and 24 elders. When the Lamb took the book with the seven seals, the 24 elders fell down before the Lamb in worship, "each one having a harp and golden bowls of incenses, which are the prayers of the saints."
Similarly, in Revelation 8:3-4 we are told that something similar happened when the Lamb opened the seventh seal of the book: "Another angel came and stood on the altar, having a golden censer, and many incenses were given to him, in order that he will give it with the prayers of all the saints on the golden altar before the throne. And the smoke of the incenses went up with the prayers of the saints from the hand of the angel before God."