One of things I'd like to do with some of my beach photography is change colors to pastels (which basically means adding white to the colors). I haven't figured a way to do this in Photoshop. Any ideas out there?

As you've probably discovered by now - there is never only one way to do something in Photoshop. When you say you want to "add white" to colors you are basically saying you either want to make it "brighter" - or you want to actually make it whiter which means you want to "desaturate" it.

Double-click the Background layer and make it a regular layer - then add a layer underneath it and fill that with white. Now you can decrease the Opacity of your image layer and that will make the entire image more pastel - you are, in effect, brightening the entire image.

If you want to change just a single color within the image - add a Hue & Saturation layer - hold down the Shift key while you drag the Eyedropper through the area you want to change - then drag the Brightness slider to the right, or the Saturation slider to the left. Voila!

Thank You! I will give these a try to see if it's the effect I'm looking for.