Google brings up this short piece by him,
Becoming Muslim
Yahiye Adam Gadahn
My first seventeen years have been a bit different than the youth experienced by most Americans. I grew up on an extremely rural goat ranch in Western Riverside County, California, where my family raises on average 150 to 200 animals for milk, cheese, and meat. My father is a halal butcher (a butcher who slaughters in an Islamic manner -ed.) and supplies to an Islamic Food Mart a few blocks from the Islamic Center in downtown Los Angeles.
My father was raised agnostic or atheist, but he became a believer in One God when he picked up a Bible left on the beach. He once had a number of Muslim friends, but they've all moved out of California now. My mother was raised Catholic, so she leans towards Christianity (although she, like my father, disregards the Trinity). I and my siblings were/are home-schooled, and as you may know, most home-school families are Christian. In the last 8 or so years, we have been involved with some home-schooling support groups, thus acquainting me with fundamentalist Christianity. It was an eye-opening experience. Setting aside the blind dogmatism and charismatic wackiness, it was quite a shock to me when I realized that these people, in their prayers, were actually praying TO JESUS. You see, I had always believed that Jesus (pbuh) was, at the very most, the Son of God (since that is what the Bible mistranslates "Servant of God" as). As I learned that belief in the Trinity, something I find absolutely ridiculous, is considered by most Christians to be a prerequisite for salvation, I gradually realized I could not be a Christian.
In the meantime, I had become obsessed with demonic Heavy Metal music, something the rest of my family (as I now realize, rightfully so) was not happy with. My entire life was focused on expanding my music collection. I eschewed personal cleanliness and let my room reach an unbelievable state of disarray. My relationship with my parents became strained, although only intermittently so. I am sorry even as I write this.
Earlier this year, I began to listen to the apocalyptic ramblings of Christian radio's "prophecy experts." Their paranoid espousal of various conspiracy theories, rabid support of Israel and religious Zionism, and fiery preaching about the "Islamic Threat" held for me a strange fascination. Why? Well, I suppose it was simply the need I was feeling to fill that void I had created for myself. In any case, I soon found that the beliefs these evangelists held, such as Original Sin and the Infallibility of "God's Word", were not in agreement with my theological ideas (not to mention the Bible) and I began to look for something else to hold onto.
more..
http://www.usc.edu/dept/MSA/newmuslims/yahiye.html