Flatterner?

Is there a way to automatically roll out a round object, like a cylinder, so that it is flat in 3ds max6?

no I don't think so, and why would you wanna do that?

scale em flat =P (to the z axis)
still your stuck with lots of useless polys so you have to cut away the half of the circle 9bottom) and then flatten the rest, then use optimize (or you can also just use the top of a cyclinder and delete the rest)

Well, is that how you unwrap them?

.....you werent talking about that, besides just apply a uvwrap on that thing, make it planar in your case and done