So my personal recommendation is Altium, but that's really expensive. The cheapest way there is (and I do know some engineers who do this on a regular basis with great success) is to draw (by hand/in visio/whatever) a schematic and then....hold your breath...type up a netlist in a format that the layout tool will recognize. I'm not saying that this is the modern way or the best way or the way I'd do it, but it's always a possibility and in reality, if you're careful, it's totally possible and not all that bad.

D