First off, let's get something straight: Islam is a violent religion. The Koran clearly states that "believers" are expected to cleanse the world of "infadels." Translation: mulsims are supposed to kill non-muslims.
Along these lines, here is an additional link declaring why the fatwa is bogus.
As Christians, we are to love these people. They are the way they are because they don't believe in the God (the God of Abraham, Isaac, and Jacob). They need to know that God isn't impersonal. He loves us and wants a relationship with us. That relationship comes after we are made right by the sacrifice of His Son, Jesus (Isa), on the cross. He was crucified, died, and rose again three days later.
Christians, if we don't tell, who will?!