Photoshop CS3 Tutorial
How to Apply a Selective Blur in Photoshop
Since the eye is drawn to in-focus objects, you may want to de-emphasize areas of your image by blurring. This method allows you to blur selected areas.
Open an image in Photoshop (File > Open).
Choose Filter > Blur > Gaussian Blur. The Preview box should be checked. Your entire image will blur, but just watch the less important background objects.
Open the History palette (Window > History) and click the History Brush box for the Gaussian Blur step. This is the version that your brush uses to paint the image.
Click the step name just above the Gaussian Blur step. This takes the image back to what it looked like before blurring.
Select the History Brush tool. Set the Blending Mode to Normal in the brush options.
Paint the areas to blur with the History Brush. Use a soft edged brush and vary the opacity and size if desired.