I use Photoshop CS4, I'm not sure about the layout of previous versions.
Original:
1. Open your image and enter in Quickmask Mode.
2. Select the Gradient Tool, make sure the Reflected Gradient option is selected, and also the 3 check boxes should be active.
3. Click on the focal point of your picture, and make a vertical line (slightly off center produces better results).
4. Go back into Standard Mode.
5. Filter -> Blur -> Lens Blur. The Radius should be between 10-20 for best results, and the next 2 sliders at 0. Select ok.
6. Image -> Adjustments -> Curves.
Final Version: