  We use the COBE Differential Microwave Radiometers (DMR) 4-year sky maps to
model Galactic microwave emission at high latitudes (|b| > 20 deg).
Cross-correlation of the DMR maps with Galactic template maps detects
fluctuations in the high-latitude microwave sky brightness with the angular
variation of the DIRBE far-infrared dust maps and a frequency dependence
consistent with a superposition of dust and free-free emission. We find no
significant correlations between the DMR maps and various synchrotron
templates. On the largest angular scales (e.g., quadrupole), Galactic emission
is comparable in amplitude to the anisotropy in the cosmic microwave background
(CMB). The CMB quadrupole amplitude, after correction for Galactic emission,
has amplitude $Q_{rms}$ = 10.7 uK with random uncertainty 3.6 uK and systematic
uncertainty 7.1 uK from uncertainty in our knowledge of Galactic microwave
emission.
