BatchBlitz lets you batch-process your photos using customizable actions. You can save your action settings to a task file and reuse it later.

Actions allow you to filter source files (using regular expressions, for example), rename and convert images, as well as add watermarks, resize/rotate canvas, apply automatic color corrections, etc. The instant preview will give you a better idea of the actual effects.
In a typical batch processing task, you simply select some source images, specify where and how to store the output files, define one or more actions, and then start the task with a click.