At the PS Conference last week, I learned a sharpening trick that's becoming standard.
If you're looking to sharpen only certain parts of your image, you can create a Layer Mask and paint over it in the opposite color in selected areas to reveal a sharpened layer. I'm posting the steps below in case anyone needs the same effect. I have CS5
Using a model pic as an example, you want her eyes, lips and hair to be sharp, but not necessarily her entire face.
The original image.
Make a duplicate layer of the background and sharpen it to where you want the eyes etc to be. As you can see here, it's not especially flattering in other areas as is.
Next, add a Layer Mask over the sharpened layer. You can do this by selecting the sharpened layer and then making the following menu selection: Layer->Layer Mask->Hide All. You will see a black rectangle icon in that layer line.
To reveal only the areas of sharpness you want, you paint over that layer using a white brush. Just select the brush, make the foreground color white, select your size and type brush (use a soft brush), and paint over the areas you want sharp. The instructor said that you generally want to sharpen areas of detail that are flattering, like eyes and hair. I hit the eyes, mouth, eyebrows and hair. You will now have a selectively sharpened image!
What it does is create a mask with holes. I turned off the main background layer and took a screen shot to show what the layer mask looks like with the model's features showing through.