Steve, if you figure out how to avoid the purple fringe against a bright sky, please let me know.
Well, avoiding it might be luck, although I have noticed the better the shot (meaning little or no post-processing needed, the less fringing there is. Here are 3 photos. First is full of it, second is same photo after I played with magenta and blue sliders in color adjustment section of Enhance in Elements. No other processing done to it. Third is same bird, but I increased shutter speed (perhaps a bit too much) to try and get him taking off, and there is none or virtually none in that shot. It is cropped and lightened a bit but no color enhancements. These are medium sized on flickr. Go there and look at full size, especially the first one, to see all the color. I chose this one because of the colored leg of the bird.