  We present emission line polarimetry data and modelling relevant to the
circumstellar geometry and kinematics around pre-main sequence stars. For a
sample of both Herbig Ae/Be stars and T Tauri stars, we find that most show
polarization changes across Halpha, implying that flattened structures are
common on the smallest scales -- and over a range of stellar masses. We also
present Monte Carlo calculations of spectral line profiles scattered in
rotating accretion disks. We consider both the case of a central star that
emits line photons uniformly, as well as via hot spots. Intriguingly, the
switch between a uniform point source and a finite-sized star results in a
marked difference in the position angle variation across the line. Our models
demonstrate the diagnostic potential of line polarimetry in determining the
disk inclination and the size of the inner hole -- a spatial scale no other
technique currently accesses.
