Is it possible to change the text bubbles on the s3? I just am trying to figure out how to change the backgrounds behind text messages. Is there a setting or some app which lets you do this?
Go to the Messaging app and hit the settings button. You will see Bubble style and Background style.  

When you select Bubble Style you will see options at the bottom of the screen that you can scroll through (the top option is the look for your outgoing messages, the bottom option is the look for received messages).

When you select Background style there are a few options to scroll through at the bottom of the screen as well.