  We study domain wall (DW) dynamics in permalloy nanowires excited by
alternating spin-polarized current applied perpendicular to the nanowire. Spin
torque ferromagnetic resonance measurements reveal that DW oscillations at a
pinning site in the nanowire can be excited with velocities as high as 800 m/s
at current densities below 10$^7$ A/cm$^2$.
