Family Search has just released a new database of Pennsylvania Civil Marriages, spanning the years 1677 – 1950. You’ll need to create an account, if you don’t have one already, and be logged in to see the images. The images are from various counties, with a large portion from Philadelphia.
If you’ve never visited Family Search, you really should. Their records are free and their site is easy to navigate. You can even create your family tree there and add records that you find.