I've just upgraded to Photoshop Elements 6 from 5 but hadn't been particularly impressed with any new features, until today. Today I discovered a feature (I won't say undocumented) that I hadn't heard of that allows you to batch watermark photos.

I've been looking for a feature like this so that I can watermark photos before uploading them to a photo hosting site. Lightroom has this feature but you are limited to putting the watermark in the corner (which is easily cropped off). But Elements lets you put it across the middle, choose the color/size/style of font.

To access this feature, open Elements 6 Editor.
Select File, Process Multiple Files.
Select the folder with the files in it or choose Open Files (to use the files open in the project bin).
In the right pane, select the Labels down arrow and choose watermark from the drop down.
Now type in the text you want, choose a font, size, color and opacity.
Edit: Make sure you have selected the Max Quality JPEG.
Then click OK.

Your window will look something like this, once complete.