Christianity Today's January 2013 cover story is all about Islam and more particularly Insider Movements as to how Muslim converts to Christianity can remain in Islam and still worship Christ. I offer no commentary here, but the article authors do include Phil Parshall and John Travis.
Discipleship is Messy - Editorial
How Much Muslim Context Is Too Much for the Gospel? by Phil Parshall
Why Evangelicals Should Be Thankful for Muslim Insiders by John J. Travis
Worshiping Jesus in the Mosque by Gene Daniels
The Hidden History of Insider Movements by Timothy C. Tennant
I should note that I have taken a class under Phil Parshall, so I'm "partial" to his line of thinking. Travis is the "father" of the C1-C6 spectrum in contextualization while I would consider Parshall to the "father" of modern-day contextualization. Tennant used to teach at my Alma Mater, Toccoa Falls College, but left right before I went to school there. My wife may have had him for a professor, however. Anyways, "Insider Movements" are a heated topic in missiological circles right now. Let's keep this civil.