Nikon D90 and D5000 owners must know that firmware update is out at last. Go for it! Hey, don't hurry! Click on USEFULL first! :D
"Distortion control data are used to correct barrel and pincushion distortion during shooting and editing."
To perform the update read this: http://nikonimglib.com/dcdata/manual/En/lensprofile_win_en_ABF.html
Good luck and no more distorsions!
It's work on snow, too.