Yes, there will be a fourth movie. It is scheduled for release in December 2010. Little is known about the movie thus far, though trailers indicate it will have to do with Ichigo's new Hollow form.
Yeah there is a 4th movie and in the पूर्व दर्शन it says "What will happen to ichigo?!"and it shows a picture of ichigo in his vasto lorde form.(sorry if i spelled it wrong.)So i'm guessing its about ichigo losing controll of his inner hollow.
