why not pass it to the func?
function listpeople($f_people)
{
// use $f_people here
}
// call with
listpeople($people);
if you want to change the array inside the function:
function listpeople(&$f_people) // note the &, a reference
{
// use $f_people here
}
// call with
listpeople($people);
finally, I think there's the possibility to declare $people global