It's not as simple as that as you have to make sure it works correctly for both horizontal and vertical images, not so straighforward and also you may welll have to do different ones for different sized images.Nah...photoshop action is all you need.
Just open one of your image. Create an action. While it is creating proceed in to what you would do normally to add your copyright info. Once it's done. Stop your action. For batch...just go to File > Automation > Batch. Then pick the folder you want to batch and the action. That's all you have to do.
Check this tutorial for how to do this
http://av.adobe.com/russellbrown/BrandingSM.mov
Programmes like LR/Aperture on the whole are potentially much better at such things, though LR needs to improve, sorry give some decent options re placement and size.