During El Nino, the ITCZ typically moves equatorward.  With that said, in part due to increased warmth in the tropical eastern Pacific, El Ninos favor a more active eastern Pacific tropical cyclones.  

As for the Southwest U.S. summer monsoon, there is a very slight tilt toward increased rainfall.  There is more information about the SW monsoon on the CLIMAS webpage (along with podcasts that discuss current/expected conditions):  http://www.climas.arizona.edu

Monsoon: http://www.climas.arizona.edu/sw-climate/monsoon