This one confused me. I started out researching Sterling, CT's congregational church. It's a relatively small town on the Rhode Island border. The town's website indicates that it was founded in 1794. In that era, it should have had a congregational church... but doesn't. Why? A local history from the late 1890s finally pointed me in the right direction. Turns out the congregational church for Voluntown falls partially in Sterling. Who knew?
I couldn't find much on the church on the church as it exists now, but there is a nice piece on the New London Rootsweb list-serv.
There are great materials available for you to research the genealogy of Sterling families who may have attended this church. Church records were transcribed in the 1950s and should be available on microfilm, although I'm having a hard time figuring out where. Many marriage are also listed in Frederick Bailey's Early Connecticut Marriages. You can also check the Connecticut State Library. Happy research!