  X-ray sources in spiral galaxies can be approximately classified into bulge
and disk populations. The bulge (or hard) sources have X-ray colors which are
consistent with Low Mass X-ray Binaries (LMXB) but the the disk sources have
softer colors suggesting a different type of source. In this paper, we further
study the properties of hard and soft sources by constructing color segregated
X-ray Luminosity Functions (XLF) for these two populations. Since the number of
sources in any given galaxy is small, we coadded sources from a sample of
nearby, face-on spiral galaxies observed by Chandra as a Large Project in Cycle
2. We use simulations to carefully correct the XLF for completeness. The
composite hard source XLF is not consistent with a single power-law fit. At
luminosities Lx>3E38 ergs/s it is well fit by a power law with a slope that is
consistent with that found for sources in elliptical galaxies by Kim and
Fabbiano 2004. This is supports the suggestion that the hard sources are
dominated by LMXBs. In contrast, the high luminosity XLF of soft sources has a
slope similar to the ``universal'' High Mass X-ray Binary XLF. Some of these
sources are stellar mass black-hole binaries accreting at high rates in a
thermal/steep power law state. The softest sources have inferred disk
temperatures that are considerably lower than found in galactic black holes
binaries. These sources are not well understood, but some may be super-soft
ultra-luminous X-ray sources in a quiescent state as suggested by Soria et al
2009.
