Can anyone tell me where I can find the rule covering stepping out of the batter's box to swing at a pitch?

I am particularly concerned with a batter stepping out of the box to swing at a pitch and the ball going into foul territory as a result. Is the batter out? or is it merely a foul ball?

Please state the rule references for USSSA only.

Thanks.

Maybe this is what you are looking for!!!!!
<b>USSSA</b>
Rule 8 Sec 7. <b>A batter shall not hit the ball fair or foul</b>
while either foot is touching the ground completely outside of the
batter's box or while touching the <b> plate</b>.
Note: A follow through with the bat may carry one of the batter's
feet entirely outside the box so it touches the ground as the ball
is leaving the bat. It is customary for the umpire to ignore this
if both feet were in legal position at the start of the swing and
if it is not considered an attempt to circumvent the spirit of the
rule.

<B> PENALTY: The ball becomes dead immediately. The batter is out.</b>

glen