Does this plot show heteroscedasticity? I am running a multiple regression with a continuous DV and a mix of dichotomous and continuous IVs (but mostly dichotomous).  This is the ZRESID vs ZPRED scatterplot, and I think there is heteroscedasticity but i'm not sure if some of the patterns is due to the binary IVs?  Any help would be much appreciated.

At present your plot suffers from significant overplotting, which makes it impossible to see how much data is in the blob and lines appearing in the plot.  So before you do anything else you should fix your plot by using transparency for the points, so the viewer can judge the volume of data in the different parts of the plot.
Even once you have done that, it can be quite difficult to judge homo/heteroskedasticity from the standard residual plot.  It is more usual to construct a scale-location plot of the residuals for this purpose, since it is easier to see changes in variance by looking at the root-absolute residuals (see this related question).
