Joel at Connexions has an excellent post entitled What is Liberal Theology? I think I agree with most everything he's said and we even seem to come to very similar theological conclusions.
I have always said that my theology is "liberal in process and orthodox in doctrine". Joel's post points that out, I think, without necessarily using those words. I think his 22 points amount to a "way to do theology" - to a process. And, as he points out, the conclusions can be quite varied. Like him, I'm nowhere near being a Tillichian.
I expect that a lot of theological conservatives would say that having a conservative theological process is the only way to be certain that one will have orthodox outcomes. I disagree. I'd point to the fact that Jehovah's Witnesses, Christadelphians and those who believe in "The Rapture" all use conservative theological processes. Indeed, one of my bugbears - as many people will know - is that it sometimes seems to me that all you have to do is call yourself a theological conservative and then you can spout any old heresy you like and people will believe that it's orthodox.
For many of us, having "liberal" (as per Joel's post) theological processes, is the only way to be a Christian with integrity. It doesn't help Christianity to blame other Christians for the decline of the church; I think the situation is a lot more complex than that.