This is something I downloaded ages ago. It works ok for me...
Start by loading up the affected image. Now select Image/Adjustments/Hue-Saturation. [In Photoshop Elements 2, select Enhance/Adjust Color/Hue-Saturation; in Paint Shop Pro 8 select Adjust/Hue & Saturation/Hue-Saturation-Lightness].
Ok, here's the important step: click the blue channel. Do not adjust the master channel. PhotoShop takes the guesswork out of the HSL adjustment step. When the blue channel is selected, the eye dropper tool on the HSL dialog will become available. Click the leftmost eyedropper and use it to sample the purple fringe in your image. Then reduce the saturation; somewhere between -70 and -80 is usually about right, but you'll need to do this by eye as every inage is different. You can use the colour slider at the bottom (between the two color bars) to make finer adjustments.
Finally, you may find the image needs some minor tinkering and will probably appear a little washed out. Making fine adjustments to the Brightness/Contrast or Levels settings will correct these problems.