I have only heard of it until recently, when I heard that the cover artist for the Wii version used art that had been supplied for IGN. If you look closely at the cover art, you can see an almost completely transparent IGN logo next to Amaterasu's mouth, and this is for the actual case, which is just absolutely hilarious. I would really like to have it.
http://"http://blogs.ign.com/wiinint.../04/20/87271/" if you want to look into it.
This bit of silly news got me somewhat interested in Okami, so I'll look into it some more. =P