Doug, first it depends on your board size. I am 6 ft and ride a 139 and I put my bindings as far out as they can possibly go. The basic rule of thumb is to put the bindings at 'shoulder width' and try riding that, and then mess around with the placement. You need to be slightly 'ducked', meaning the toes need to be angled a little 'out' from your heels (towards the tip/tail of the board). I ride at about 12 degrees ducked. Once you get the bindings set, put them on in your living room and do several squats. If the angle feels wrong and puts weird pressure on your knees, change it up to more/less duck and see how that feels.
If you have a 139 board, for starters I would put my bindings at 1 peg in from all the way out, and give both a slight angle out (opposite from each other like this guy in the picture (no, that's not me...I wish