Cross-phase modulation (XPM) changes the state-of-polarization (SOP) of the channels through nonlinear polarization rotation and induces nonlinear time dependent phase shift for polarization components that leads to amplitude modulation of the propagating waves in a wavelength division multiplexing (WDM) system. Due to the presence of birefringence, the angle between the SOP changes randomly and as a result polarization mode dispersion (PMD) causes XPM modulation amplitude fluctuation random in the perturbed channel. In this paper we analytically determine the probability density function of the random angle between the SOP of pump and probe, and evaluation the impact of polarization mode dispersion on XPM in terms of BER, channel spacing etc. for a two channel IM-DD WDM system at 10 Gb/s. We also show the dependence of SOP variance on PMD parameter and channel spacing.