I don't want to give away all my secrets but I have to sing the praises of these Automator Actions. I've been using them since 2005 (and CS2?) to crunch large folders of images into multiple sets of web optimized jpgs at specific sizes, watermark for Ebay, and/or convert color profiles.
The brilliance of these Automator actions is that you can use them to accomplish things which can't be done via Photoshop's built-in "actions" functionality. Better yet, the Automator Actions can be used in conjunction with Photoshop's actions. And sometimes it's just more efficient to set a few values in an Automator workflow instead of doing it in Photoshop.
Basically, stuff gets done. Instead of getting a repetitive stress injury, you make a cup of tea while your machine spends a few minutes doing the busy work.
From previous comments here I can see that some folks stumbled over the learning curve. Automator has its learning curve, and these actions have a quirk or two (tip: every workflow needs to include the "Render" action). But, hey, Photoshop has a bit of a learning curve, too, in case you hadn't noticed.
If you're not doing repetitive tasks in Photoshop, then you probably don't need this.