  Scintillation observations of the nearby single millisecond pulsar (MSP) PSR
J0030+0451 were carried out with the Parkes 64m radiotelescope at three
different epochs in 1999. From analysis of the dynamic spectrum we obtained the
amplitude of the electron density power spectrum log C_N^2 ~= -3.33$ and a
scintillation velocity V_iss <~ 15 km s^-1. This result shows that the
Shklovskii effect on the spin-down rate \dot P is negligible. We also performed
a correlation analysis between pulsar proper motions (V_pm) and scintillation
velocities (V_iss) using updated measurements for a sample of 77 objects, 17 of
which are MSPs. The full sample shows a correlation coefficient r_s ~= 80% at
an extremely high significance level, while for the MSP sub-sample (excluding 2
outliers) we obtain r_s ~= 90%.
