<?php
// Assuming today is March 10th, 2001, 5:16:18 pm, and that we are in the
// Mountain Standard Time (MST) Time Zone

$today = date("F j, Y, g:i a"); // March 10, 2001, 5:16 pm
$today = date("m.d.y"); // 03.10.01
$today = date("j, n, Y"); // 10, 3, 2001
$today = date("Ymd"); // 20010310
$today = date('h-i-s, j-m-y, it is w Day'); // 05-16-18, 10-03-01, 1631 1618 6 Satpm01
$today = date('\i\t \i\s \t\h\e jS \d\a\y.'); // it is the 10th day.
$today = date("D M j G:i:s T Y"); // Sat Mar 10 17:16:18 MST 2001
$today = date('H:m:s \m \i\s\ \m\o\n\t\h'); // 17:03:18 m is month
$today = date("H:i:s"); // 17:16:18
?>

Example

<?php
echo("Result with date():<br />");
echo(date("l") . "<br />");
echo(date("l dS \of F Y h:i:s A") . "<br />");
echo("Oct 3,1975 was on a ".date("l", mktime(0,0,0,10,3,1975))."<br />");
echo(date(DATE_RFC822) . "<br />");
echo(date(DATE_ATOM,mktime(0,0,0,10,3,1975)) . "<br /><br />");

echo("Result with gmdate():<br />");
echo(gmdate("l") . "<br />");
echo(gmdate("l dS \of F Y h:i:s A") . "<br />");
echo("Oct 3,1975 was on a ".gmdate("l", mktime(0,0,0,10,3,1975))."<br />");
echo(gmdate(DATE_RFC822) . "<br />");
echo(gmdate(DATE_ATOM,mktime(0,0,0,10,3,1975)) . "<br />");
?>
===============================================
The output of the code above could be something like this:

Result with date():
Tuesday
Tuesday 24th of January 2006 02:41:22 PM
Oct 3,1975 was on a Friday
Tue, 24 Jan 2006 14:41:22 CET
1975-10-03T00:00:00+0100

Result with gmdate():
Tuesday
Tuesday 24th of January 2006 01:41:22 PM
Oct 3,1975 was on a Thursday
Tue, 24 Jan 2006 13:41:22 GMT
1975-10-02T23:00:00+0000