$time = time();
$three_am = strtotime('3am');
$ten_fifty_nine_am = strtotime('10:59am');
$eleven_am = strtotime('11am');
$four_pm = strtotime('4pm');
if ($time > $three_am && $time < $ten_fifty_nine_am)
{
// code for 1.swf
}
if ($time > $eleven_am && $time < $four_pm)
{
// code for 2.swf
}
// etc...
or a better way is to name your swf files in some meaningful way that suggests what time your want them to display and write just one statement that automatically plays the right one at the current time.