This is the time of year when Catholics are trying to inform their consciences, as our bishops recommend in Faithful Citizenship , before they cast their votes. There is a lot of stuff out there, but one piece that particularly helped me is America Undecided, Catholic, Independent & Social Justice Perspectives on Election 2012 by Ed Gaffney, Doug Kmiec and Patrick Whelan. It is available at Amazon  on a Kindle version for 99 cents. The authors do a phenomenal job of pulling together the relevant strands of Catholic social justice thought that are applicable in this election. They deal especially well with the issues raised by some thoughtful Catholics, like the HHS regs on contraceptives and the other life issues, and I highly recommend their work to anyone trying to vote with an informed conscience in this election.
Nicholas P. Cafardi