  We report the analysis of deep radio observations of the interacting galaxy
system M51 from the Very Large Array, with the goal of understanding the nature
of the population of compact radio sources in nearby spiral galaxies. We detect
107 compact radio sources, 64% of which have optical counterparts in a deep
H$\alpha$ Hubble Space Telescope image. Thirteen of the radio sources have
X-ray counterparts from a {\em Chandra} observation of M51. We find that six of
the associated H$\alpha$ sources are young supernova remnants with resolved
shells. Most of the SNRs exhibit steep radio continuum spectral indices
onsistent with synchrotron emission. We detect emission from the Type Ic SN
1994I nearly a decade after explosion: the emission ($160\pm22 \mu$Jy
beam$^{-1}$ at 20 cm, $46\pm11 \mu$Jy beam$^{-1}$ at 6cm,
$\alpha=-1.02\pm0.28$) is consistent with light curve models for Type Ib/Ic
supernovae. We detect X-ray emission from the supernova, however no optical
counterpart is present. We report on the analysis of the Seyfert 2 nucleus in
this galaxy, including the evidence for bipolar outflows from the central black
hole.
