It's far too late for them now, and McCain's not the kind of guy the evangelicals will come out for in masses.
Putting Mr. squirrel frier on the ballot might do the trick, but they're not going to do that.
It takes time to build a GOTV machine but once built regular maintenance can keep it ticking over. The Evangelical turn-out was the triumph of the GOP in '04. How much of the machine is left, how many people they can get to staff the machine, how effective the machine will be are open questions.
Given the '06 results I think it is safe to assume this machine is in need of oiling and, perhaps, a new transmission. In the GOP's favor is loosely attached, low information, voter participation and interest in politics increases in a presidential year. (Loosely attached, low information, voter pretty much defines the Evangelical block, Praise Jeebus!) A restocking, recapitulation, of this machine could, would, fly under the notice of journalists since a good deal of work could be done within existing churches and social (personal) networks.