Are Americans becoming less religious? It depends on what you mean by "religious." According to an article in the New York Times, there's plenty of evidence to suggest that the "religious mind" is still very much alive. The article notes:

Consider that roughly 30 percent of Americans report they have felt in contact with someone who has died. Nearly 20 percent believe they have been in the presence of a ghost. About one-third of Americans believe that ghosts exist and can interact with and harm humans; around two-thirds hold supernatural or paranormal beliefs of some kind, including beliefs in reincarnation, spiritual energy and psychic powers.

These numbers are much higher than they were in previous decades, when more people reported being highly religious. People who do not frequently attend church are twice as likely to believe in ghosts as those who are regular churchgoers. The less religious people are, the more likely they are to endorse empirically unsupported ideas about U.F.O.s, intelligent aliens monitoring the lives of humans and related conspiracies about a government cover-up of these phenomena.