  Planetary nebulae (PNe) can be used to trace intermediate and old stellar
populations in galaxies and the intracluster medium out to approximately 20
Mpc. PNe can be easily identified with narrow-band surveys, and their chemical
abundances and radial velocities can be measured with multi-slit or multi-fiber
spectrographs. We briefly review what has been accomplished to date, and
include tables (with references) that summarize the observations of PNe in 42
galaxies and in the intracluster media of the Virgo and Fornax clusters. The
surveys for intracluster PNe suggest that between 20% and 50% of the clusters'
total stellar mass is in the intracluster medium! We illustrate the utility of
PNe for dynamical studies by presenting results from a recently completed
survey of Cen A (NGC 5128) with the NOAO mosaic camera on the CTIO 4-m
telescope. The PNe and globular cluster surveys extend respectively to
distances of 80 Kpc and 50 Kpc. We compare the kinematics of the stars in Cen A
(736 PN velocities) to the kinematics of the red and blue globular clusters
(188 clusters with measured velocities). The latter include 125 newly confirmed
globular clusters from our survey.
