The folks at Pew Forum on Religion and Public Life have created an interactive graphic that is easy to parse and fun to use that allows unrepentant political geeks to track candidate Obama and Romney's weekly standing in specific Christian denominations, broken down even to frequency of worship attendance (h/t J. Peter Nixon at Commonweal).
Pew polls this week show Obama ahead among all Catholic voters by a wide margin, but his support drops quickly when it is limited to weekly churchgoers. He is dead even among white Catholics in general this week; an improvement, he is trending higher in this group. Weekly churchgoing white Catholics support Romney by a strong margin, monthly and seldom churchgoing white Catholics support Obama by the same.
Take a look at the graph here.