John Piper lists some Sources to Help You Speak Against Abortion. Though I once would have vehemently disagreed with his conclusion, I now concur wholeheartedly: "May the Lord give you courage to address the carnage. I find it appalling that there are pastors and churches that NEVER address this issue."
Update: Also check out Scott Klusendorf's address to 3,000 students last Wednesday at Cedarville University. It's a mix of pro-life apologetics, gospel, and tactical suggestions. In my opinion, Klusendorf is one of the most articulate, winsome defenders of life in America today.