I recently found a collateral line of mine, came from Mobile County Alabama. In researching the line, I discovered that the county has a great collection of marriage records online. The records go back pretty far. You do have to register and agree to respect the privacy of the people listed but registration is pretty easy and fast.
When you get to the site, click on "Records Search" in the lefthand column and the "Marriage Record" link and either click on "Register" or login to begin searching.