You can also read Driscoll's notes, which include links. I'll give you an excerpted version to whet your appetite:
There are five levels of birth control, ranging from no birth control to abortion. Levels 1-3 should be considered acceptable for Christian couples, level 4 is more complicated and requires prayerful consideration, and level 5 is forbidden and sinful. ....
Level 1 — No Birth Control
Some Christian couples determine to only use prayer in their family planning. As a result, they simply enjoy normal marital sexual relations and trust that if God desires for them to have a child, He will provide according to His timing. When this is chosen as the course of action by a Christian couple, family planning by simply praying and trusting that whatever happens is God’s good will is acceptable. The only problem is when this conscience preference is legalistically imposed on others as if it were the only acceptable option for a Christian married couple.
Level 2 — Natural Birth Control
Natural methods include any method of contraception where pregnancy is prevented by abstaining from vaginal sexual intercourse on days where the wife is likely to be fertile. .... Natural methods are approved for use by the Roman Catholic Church. Furthermore, abstaining from sexual intercourse does not necessarily require abstaining from all sexual activity.
Natural birth control methods have many benefits. Included among them are the fact that, unlike most forms of birth control, they involve the husband, are free, require no surgery, no chemicals, no devices, no drugs, no side effects, are safe, reversible, and can also be used with other methods such as a condom during fertile times. One of the potential difficulties is that they require discipline and planning, which not everyone is equally faithful to pursue. In conclusion, natural birth control is permissible for a Christian couple.
Level 3 — Non-Abortive Birth Control
Like the natural methods, non-abortive birth control methods also seek to influence the timing of conception but do so by taking either temporary or permanent additional measures. Temporary non-abortive birth control methods are generally barrier methods. ....
Permanent non-abortive birth control methods are those chosen by couples who have decided not to have any more children. This can be achieved either by female sterilization, also called tubal ligation, or vasectomy for men.
Three things need to be mentioned regarding permanent non-abortive birth control methods. First, the heart really needs to be examined regarding motive on this issue; this method should never be used to abandon the blessing of children. Second, it is unwise for this decision to be made too early in life because it is not uncommon for a couple to later desire more children, or for someone to become remarried after being divorced or widowed and desire to have children with their next spouse. Third, there are Christians who are legalistic on this issue and declare that there is essentially never a good reason for such a permanent measure. However, life in a fallen world is complicated and painful. For example, a pastor and his wife who are good friends of mine suffered eighteen miscarriages before he had a vasectomy to stop what had become for them incredible physical and emotional pain.
To summarize, levels 1-3 are options for Christian couples to consider without concern that they may terminate a fertilized egg and thereby take a human life. At the next level we tread into more murky waters that are more difficult to discern for Christian couples.
Level 4 — Potentially Abortive Birth Control
The pill is a categorical term for more than forty types of oral contraceptives, which are also referred to as birth control pills and sometimes combination pills because they contain a mixture of estrogen and progestin. These hormonal contraceptives are designed to override the female body’s normal cycle and “trick” the brain into believing she’s already pregnant, thus preventing the release of an egg from the ovaries.
[Driscoll reviews the evidence of potential abortifacient effects of the Pill. The research I've seen indicates that breakthrough ovulation results in enough of the woman's own hormones to override the effects of the Pill. In short -- there is suspicion, evidence, and belief, but no conclusive proof, that the Pill prevents implantation.]
The bottom line is this, the first two purposes for birth control pills are contraceptive in nature and therefore acceptable for use by a Christian couple. However, the third use of birth control pills is potentially abortive in that it seeks to disrupt the ongoing life of a fertilized egg. That potentiality is incredibly controversial; thus, faithful Christians who are staunchly pro-life and believe that life begins at conception are divided over the issue. Even Focus on the Family and the Christian Medical and Dental Associations (CMDA) are undecided on the issue.
Therefore, whether or not a Christian couple should use birth control pills is a very complicated issue on which faithful pro-life Christians and doctors disagree. As a result, it seems legalistic and inappropriate to declare that use of the pill is sinful. Yet, at the same time it seems that Christian couples need to be informed of the potential abortive nature of birth control pills so that they can study the matter further and prayerfully come to an informed decision according to their own conscience and the leading of God the Holy Spirit.
Level 5 — Abortive Murder
Abortion is the taking of a human life through the killing of a fertilized egg. Biblically, it is also known as the sin of murder. Abortions include medical procedures of various kinds as well as RU-486 or the morning-after pill. Other items that cause abortion are the intrauterine device (IUD) and Norplant, which do not prevent conception but prevent implantation of an already fertilized ovum. The result is an abortion, the killing of a conceived person.
It may seem odd for me, as a pastor writing primarily for Christian readers, to include this level as a form of birth control. Yet, tragically, many people, including Christians, use abortion as a form of birth control. Undoubtedly, there are very rare cases where even the most devoutly Bible-believing, pro-life Christians are caught on the horns of an ethical dilemma involving abortion (e.g., when the mother’s life is at stake), but for the purposes of this blog I am speaking of abortion in its majority sense as a murderous form of birth control. ....
Some will argue that there is a difference between a child in a mother’s womb and one outside, yet the early church saw both as equally living people and the taking of life in either state as equally murderous. Their convictions were based on Scripture, which uses the same word (brephos) for Elizabeth’s unborn child John the Baptizer in Luke 1:41, 44, as is used for the unborn baby Jesus in Mary’s womb in Luke 2:12, and also for the children brought to Jesus in Luke 18:15. ....
Thankfully, Jesus can forgive any sin, even the sin of murder, as he did while hanging on the cross and asking God the Father to forgive those who murdered him. Furthermore, pro-life ministries are devoted to extending the love, grace, mercy, compassion, and support needed for men and women who have suffered from abortion to experience healing and new life. In our church this includes a ministry to post-abortive women run by female deacons who were once sexually active, fornicating feminists who aborted their own children only later to meet Jesus, repent, experience new life, and become godly wives, mothers, and church leaders.
In summary, as a pastor I would support Christian couples practicing levels 1-3 of birth control, urge those considering level 4 to prayerfully and carefully reflect on their decision, and oppose any Christian couple considering level 5, unless there were extremely weighty extenuating circumstances. In eleven years as the pastor of Mars Hill Church, which has seen hundreds and hundreds of weddings and pregnancies, I have not yet faced such circumstances and by God’s grace pray I never do. Should that occasion occur, I would work with the family, aided by prayer from our church, counsel from my fellow elders, and outside expert medical counsel to arrive at a decision based on carefully examining all of the variables involved.