Not much details have been revealed yet apart from that it is planned for a 2007 February release. It will be a mystery based, detective visual novel game so you can expect it to be text heavy. Whether it will conform to the Manga storyline or not is unknown.

Death Note is a popular Japanese Manga that revolves around a certain dark notebook that belongs to a Death God. Whoever's name is written in it dies of either a heart attack or in any way the notebook owner wishes the victim to.

Source: Nintendo Inside
Related Links: Official Site, Death Note Movie (First Part), JP Manga Site.