not yet
if you want to use prman with maya you will have to use MTOR ..(maya to renderman) a part of the package of RAT - renderman artist tools, it includes MTOR,prman and slim(shader creation for prman). RAT4.5 is in the works by pixar and i think already released .. or atleast being close to get out. 4.5 is the only version that supports maya4.0 the rib exporter script is..well.. kinda lame if u ask me.. unless u know how to write u´r own complex sl. (shader files) in a text editor...
