John Cowley over at Lonestardigital.com has just put up a simple but effective technique for correcting the magenta / cyan casts on Nikon D1 images. There have been many programs created for fixing this common complaint with Nikon's Digital SLR, but this (at least for Photoshop users) seems to be the most straightforward yet effective. My understanding is the problem revolves around the fact that the D1's images are in the NTSC colourspace.

UPDATE: Thanks to Timo Autiokrai for noting that Photoshop Profile-to-Profile seems to work quite well to. The battle hots up... Mike Chaney gets involved!!