Evidence for the presence of relatively large amplitude right-hand elliptically polarized MHD waves upstream and downstream of quasi-parallel (&thgr;Bn<45¿) forward and reverse interplanetary shocks is presented. The mode is observed with frequencies in the range of 0.025-0.17 Hz (in the spacecraft frame) and propagates along the magnetic field. The MHD modes have rest frame frequencies in the range 3.8-31 mHz, with typical wavelengths about 1.5¿108 to 4.7¿108 cm. The magnetic field power spectrum in the vicinity of these interplanetary shocks is much steeper than f-5/3 at high frequencies. The obseerved spectra have a high frequency dependence of f-2.5 to f-4. A peculiar feature of the fast mode identification in one event is the large correlation observed between ‖B‖ and proton density p for field-aligned propagation. This appers to be a nonlinear effect, second order in the wave amplitude. The properties of the MHD waves can be understood in terms of the electromagnetic ion-cyclotron instability. Both resonant and nonresonant interactions need be considered to account for the polarization and spectral content of the observed fluctuations. In association with one event, a distinct suprathermal component was observed in the solar wind proton distribution. The parameters of this distribution are adequate to drive a resonant instability with a maximum growth rate that coincides with the observed range of frequencies.