One of the first questions in the Q&A time at O.U. was posed by a sociology professor who had done work among Muslims in Indonesia. Her question was simple: "Do Muslims worship the same God as Christians?"
My summary answer was this: the short answer is no. I gave two brief reasons: (1) the NT insists that the one who does not honor the Son does not honor the Father (John 5:23); (2) the NT claims that Jesus is God. Since Muslims do not worship Jesus as God, I think it is misleading at best and damaging at worst to say that Christians and Muslims worship the same God.
Now admittedly that was a simple and short answer; there are more issues to be addressed. That is why I want to point your attention to a recent post by my friend Justin Taylor. He traces the recent important discussion of this question, complete with links to statements by Rick Love (former international director for Frontiers) and the responses by John Piper. These are crucial issues for us as evangelicals to undertstand and to be able to articulate.