As Oklahoma goes, Norman is hotbed of liberalism - between the election of Cindy Rosenthal as mayor and the passing of a recycling initiative, we are cutting edge. But as liberal progressive Christianity goes, I was only aware of St. Stephens UMC. However, googling around led me to Dr. Bruce Prescott, executive director of Mainstream Oklahoma Baptists, president of the Oklahoma Chapter of Americans United for Separation of Church and State and host of "Religious Talk", an AM radio talk show. In 2004 Frederick Clarkson featured him in a post entitled Blogging the Christian Left (in which he also features "Pastor Dan", who was then blogging at Faithforward (and now, primarily at Street Prophets, a site I really wish I read more).
I'm rather curious about Prescott - Clarkson reported that he had two blogs: Mainstream Baptist and Christian Democrats - the former appears to be active, the latter hasn't been updated since September 2006. I'm curious about the wider world of progressive Christianity in Norman.