Welcome to the forums, Big Tim!
I know ihome and Philips make android radio docks. Since the S3 has a bottom usb port, they actually fit ok. Only thing is, Usb audio enabled docks are still scarce. Most of the docks that are available stream audio via Bluetooth or through the 3.5 mm head phone jack. Audio through usb was enabled on Jellybean devices this year so these docks that support that feature isn't too popular yet. Gear4 is the only company I know that is working on an Android dock that utilizes usb audio.
I'm gonna move this to the S3 forums because maybe some other person has more info. I'll send you a link.
Have a good one!
id does... your ph