  We present the global X-ray properties of the point source population in the
grand-design spiral galaxy M101, as seen with XMM-Newton. 108 X-ray sources are
detected within the D25 ellipse of M101, of which ~24 are estimated to be
background sources. Multiwavelength cross-correlations show that 20 sources are
coincident with HII regions and/or supernova remnants (SNRs), 7 have
identified/candidate background galaxy counterparts, 6 are coincident with
foreground stars and one has a radio counterpart. We apply an X-ray colour
classification scheme to split the source population into different types.
Approximately 60 per cent of the population can be classified as X-ray binaries
(XRBs), although there is source contamination from background AGN in this
category as they have similar spectral shapes in the X-ray regime. Fifteen
sources have X-ray colours consistent with supernova remnants (SNRs), three of
which correlate with known SNR/HII radio sources. We also detect 14 candidate
supersoft sources, with significant detections in the softest X-ray band (0.3-1
keV) only. Sixteen sources display short-term variability during the XMM-Newton
observation, twelve of which fall into the XRB category, giving additional
evidence of their accreting nature. Using archival Chandra & ROSAT HRI data, we
find that ~40 per cent of the XMM sources show long-term variability over a
baseline of up to ~10 years, and eight sources display potential transient
behaviour between observations. Sources with significant flux variations
between the XMM and Chandra observations show a mixture of softening and
hardening with increasing luminosity. The spectral and timing properties of the
sources coincident with M101 confirm that its X-ray source population is
dominated by accreting XRBs (abridged).
