We consider systems of Dp-branes in the presence of a nonzero B field. We s
tudy the corresponding supergravity solutions in the limit where the branes
worldvolume theories decouple from gravity. These provide dual description
s of large N noncommutative field theories. We analyse the phase structure
of the theories and the validity of the different description. We provide e
vidence that in the presence of a nonzero B field the worldvolume theory of
D6 branes may decouple from gravity. We analyse the systems of M5 branes a
nd NS5 branes in the presence of a nonzero C field and nonzero RR fields, r
espectively. Finally, we study the Wilson loops (surfaces) using the dual d
escriptions.