Obama is a Christian and a member of the Trinity United Trinity Church of Christ. (Note: the church has been erroneously referred to as black supremacist. See the debunking of the myth.)
Obama gave the Keynote Address at the Call to Renewal's Building a Covenant for a New America conference. In his speech, he discusses the role of religion in politics. It's in 6 parts below and should be watched as a whole. (If you don't want to watch the embedded videos, you can use this Youtube playlist ) You can read the speech here. Gay conservative author and blogger Andrew Sullivan called it, "the finest public speech on religion in public life in years."