Pro-Choice: Favoring or supporting the legal right of women and girls to choose whether or not to continue a pregnancy to term. Note that it doesn't say "likes killing fetuses" or "pro-abortion". It just says that you support the fact that women can choose what to do with their own bodies.
Pro-Life: Advocating full legal protection of human embryos or fetuses, especially by opposing legalized abortion.
Abortion: the expulsion of an embryo or fetus before it is viable. (Viable - able to live on its own outside the uterus)
Now that we know the basics, let's see what exactly the big debate about it is:
The Argument for Pro-Life: Those who say they are Pro-Life are of the belief that a baby's "life" begins at conception, which is the meeting of the egg and sperm. They say that aborting the fetus, since it is alive, equals murder, and can't be allowed.
The Arguments for Choice - Women and men who are Pro-Choice argue that the Pro-Choice argument is 1% about abortion and 99% about women's rights. Women need control over their own bodies in order to be equal citizens. If they don't have the right to choose to have an abortion, she can be raped, get pregnant, and lose her ability to have a successful career. She can't become equal in the workforce, because many women generally don't have enough time and income to care for children as well as work a job, especially if they are single mothers. They also generally agree that legalized abortions are MUCH safer for women, as the illegal abortions that were already occuring before Roe v.s Wade (the Supreme Court Case legalizing abortions) were the cause of death for countless women (4.1 per 100,000 abortions to currently 0.6 per 100,000).
Women who are Pro-Choice are generally NOT in favor of abortion as the first answer. Conversations like, "Hey, I'm pregnant, let's abort the sucker so I can get to work!" aren't particularly common among informed pro-choice women. Pro-Choice women advocate Sex Education focusing on understanding contraception, sexually transmitted disease and sexual orientation, in order to educate the public about safe sexual relations. Better to learn about how to do it safely first, than have to choose whether or not to abort it later.
Pro-Lifers favor Abstinence-Only education. "Instead of a comprehensive review of the facts about contraception, safer sex practices, and sexuality, they often receive false and exaggerated information about contraceptive failure and are told that contraceptives undermine romance and spontaneity. They typically learn about homosexuality only in the context of HIV/AIDS. Abortion is presented as morally wrong and physically and emotionally dangerous. In some programs, fetuses are referred to as "babies."" (National Coalition Against Censorship) This is dangerous, as well as misguided. Fetuses are NOT babies. Babies can live on their own outside of a body, fetuses cannot.
So, what is the verdict? Pro-Choice or Pro-life?
Pro-choice. If women can't control their own reproductive system, they don't have control over their social and economic lives. Women will never become equal if abortion is illegalized.
Further Information about Choice:
http://www.ncac.org/cen_news/cn80sexeducation.html
http://www.prochoiceresource.org/issue/iss_int.html
http://www.elroy.net/ehr/abortion.html
http://www.naral.org/takeaction/march.cfm