Chromatic aberration appears in photos as "fringes" of color along boundaries that separate dark and bright parts of the image and can be most annoying.
Even with Canon L glass and a reasonably high end camera, I'm still faced with it in certain situations - with trees against pale skies, for example, or the edges of a building against a white sky, or blue sky with clouds.
There are times when even my software (Photoshop CS5) can't completely eradicate it, so I've figured out a fix which works nicely to address this.
With your image open in PS, select the Lasso tool and draw a selection around the offending area. Then, go to the Hue/Saturation adjustments panel, and instead of Master, click on the drop down arrow and choose Cyans...then pull the saturation slider to the left until your cyan fringe disappears. Repeat with the Magentas too and this should deal with the problem.
I've also used this method for purple fringing but be aware it won't work well if you have blue sky in your image, as pulling the Blues or Cyans sliders will also affect the color of the sky.