  We study spectra of alloy-type random Schr\"odinger operators on metric
graphs. For finite edge subsets of general graphs we prove a Wegner estimate
which is linear in the volume (i.e. the number of edges) and the length of the
considered energy interval. The single site potential of the alloy-type model
needs to have fixed sign, but the considered metric graph does not need to have
a periodic structure. The second result we obtain is an exhaustion construction
of the integrated density of states for ergodic random Schr\"odinger operators
on metric graphs with a $\ZZ^{\nu}$-structure. For certain models the two above
results together imply the Lipschitz continuity of the integrated density of
states.
