To get things started, SH, a homeschool mom in Southern CA, sent me a question.
What one book would you recommend to a very misinformed young earther who has about as much scientific background as most Christian, public school graduates?
Ok, it sounds like the person in question is a Christian who has been exposed to young-earth ideas, but has minimal advanced education about science.
Believe it or not, that pretty much described me not that long ago. I hadn't really heard of any other view besides young-earth. It took me several years of careful study and reflection to crawl out of that web of ideas. Why? Because I wanted to make very, very sure that what I was crawing into was firmly grounded in Scripture.
Ok, enough biography. Let's get to S's question. A lot of it depends on what your friend's specific questions are and how committed she is to the young-earth position. If you look in the "Is billions of years biblical?" section of the right sidebar, you'll see a number of resources related to this discussion. If you click on those links, you can read specific descriptions for each one.
Is your friend concerned about animal death before Adam? Then I'd probably recommend the audio series, "Life and Death in Eden." It is very lay-friendly and answers all of the major objections in a very biblically-based way.
Is her concern about whether or not we can trust the findings of secular scientists? Then I'd suggest a different audio series, called "God's Two Part Harmony."
Does your friend have a strong aversion to Hugh Ross and scientists in general? Then maybe consider Jack Collins' Science & Faith. He is an Old Testament theologian at Covenant Seminary.
Does your friend have objections to old-earth creationist interpretation of a geographically local flood? Then I'd recommend an audio message, "Noah's Flood: Global or Local?"
Is your friend a pastor who needs more sophisticated biblical exegesis about the details of the text? Then I'd recommend, The Genesis Debate or Jack Collins' new commentary, Genesis 1-4.
Hope this is helpful. If not, post a comment and I'll follow up.