I have never attended a church service across about 6 denominations that ever even cared to mention Mohammed at a service. In fact I have never attended a church service in a similar vein where the focus was on attacking ANY other religion.
That you DO get this in church IMO is scary and indicative of some American Christian's tendencies to focus less on Christ and more on the world. When you are in His house, what matter is Mohammed to the praise and preaching of the word of God? Moreover what use is comparing Jesus to Mohammed? Are they afraid that somehow the Gospel is so weak that they must explicitly quantify how Christ is better than the figurehead of other religions?
No smoking signs by gas stations. No religion in the public square. The government should keep us from being engulfed in flames on earth, and that is pretty much it. -- Jon Stewart, The Daily Show