A recent USA Today/Gallop poll finds that, relative to twelve months ago, the number of American donating money to churches has not changed and the number of Americans volunteering at churches has increased.
This second finding is intuitive: if people out of work have a lower opportunity cost of time, they may devote it to religious volunteering. The article does not specify what type of volunteering is done, and that would be informative. Perhaps some volunteering may also serve indirectly to help networking for job opportunities.
The first finding may seem counter intuitive, but later in the article you read that people are donating less money rather than not donating at all. If incomes take hit, this is not surprising. The benefits associated with religious giving may not have changed dramatically during the recession, but the cost of giving up part of your now lower income may be higher than before. People reduce the amounts they give but not down to nothing.
Seems like our simple economics logic does pretty well explaining this pattern found in the poll.