The general form of the \pscircle is
\pscircle*[settings](x0,y0){radius} Is there a way to known all available settings?
For the line:
linewidth linecolor linestyle dash dotsep doubleline doublesep doublecolor dimen border bordercolor shadow shadowsize shadowangle shadowcolor for the filling:
fillcolor fillstyle shapealpha hatchsep hatchsepinc hatchwidth hatchwidthinc hatchcolor hatchangle addfillstyle opacity strokeopacity See also http://www.siart.de/typografie/pstricks-referenz.pdf (only in German)
\pscircle. I do not know such a list and unfortunately the pstricks manual neither provides such a list nor does it explicitly document for each parameter which commands do support them. So reading the manual is not enough. For some parameters it is obvious, whether\pscirclesupports them or not. But for some parameters and at least for a pstricks novice it is indeed not always obvious.