http://www.reuters.com/article/topNews/idUSL1162787420071011
snip...
Aref Ali Nayed, one of the signatories and a senior adviser to the Cambridge Interfaith Program at Cambridge University in Britain, said the signatories represented the "99.9 percent of Muslims" who follow mainstream schools and oppose extremism.
"In Islam we have had a problem for some time now where the mainstream voices are drowned out by a minority that choose violence," he said.
Nayed said organizers of the letter had set up an ad hoc network among Muslim leaders that could lead to more cooperation in future.
"These people don't take their signatures lightly," he said. "We are trying to institutionalize this so we don't lose it.
The overture to Christians could be followed by similar letters addressed to Jews or secularists, he added."
Sounds legitimate to me. Stay tuned.