John Tartar wrote:
Does anyone know of a simple, but free PCB layout software.

Or a way to convert .pcb files from EXPRESSPCB to industry standard format.

I currently use ExpressPCBs layout s/w which is fine for my applications
and great for prototypes. But I want the option to use other vendors when
the volume gets high, i.e. selling kits.

I'm using Eagle. I like it just fine. You can do 80x100mm 2-layer
boards for free, and the step up to bigger 4-layer boards is either $50
or $150 -- in either case it's cheap.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html