hspice sweep parameter
This is probably most straigh-forward using HSpice.
First diode connect a transistor of any size and connect a DC source to the gate/drain. That will be your DC sweep.
Add the following lines to your spice deck.
.probe vstar = par('2*i(m1)/gmo(m1)')
.probe id = par('i(m1)')
This is assuming you have named your transistor "M1."
This creates the variables vstar and id in the choices when you go to plot the data. I believe they can be found under the "parameters" category in AWaves. I haven't done this recently, so I don't remember the exact names of the windows and such. But look around the AWaves window. You can also choose to set vstar as the x-axis, which is what you want.