I copied this from Anime News Network:
This year's 37th issue of Shueisha's Weekly Shonen Jump magazine is announcing on Monday that Ryohgo Narita, the author of the Durarara!! and Baccano! light novels, will write a novel based on Tite Kubo's Bleach manga. The announcement indicates that the main character of the novel will be Don Kanonji. The novel is part of the 10th anniversary celebration for Bleach.