I wrote myself a little snippet to do this, as it comes up so often:
<?php
/*
Name: DateFormatter
Description: <strong>0.1</strong> Outputs the formatted version of the passed in UnixTimeStamp, according to the format string passed in FormatString
Version: 0.2
Author: Duncan Lock <[email protected]>
Parameters:
$FormatString PHP format string appropriate for using with the date function (http://www.php.net/date)
$DateTime Unixtimestamp or a date. If it's is_numeric, we assume it's a unix timestamp.
eg:
[[DateFormatter? &formatString=`l dS \of F Y h:i:s A` &dateTime=`[*pub_date*]` ]]
Returns something like: 'Monday 15th of August 2005 03:12:46 PM'
[[DateFormatter? &formatString=`d/m/Y` &dateTime=`1134086400` ]]
Returns something like: '09/12/2005'
*/
$formatString = isset($formatString)? $formatString: 'l jS \of F Y h:i:s A';
# Convert $dateTime into a unix timestamp, if it isn't already
$unixTimeStamp = is_numeric($dateTime)? $dateTime: strtotime($dateTime);
if (trim($unixTimeStamp) == ''):
# empty timestamp, bail
return '';
else:
# return the formatted datetime
return date ($formatString, $unixTimeStamp);
endif;
?>
As previously mentioned, you can use PHX for this, if you’re using it - and I’m sure there’s stuff in the repository that does this too. I think that I originally wrote this because I couldn’t find one that used date() - which allows you to output stuff that looks like this: ’Monday 15th of August 2005 03:12:46 PM’ - using st/th/rd for days - something you can get out of strftime(), afaik. Hope else someone finds it useful.
☆ A M B ☆
Personally I find date() more flexible and easier to comprehend than all those percenty conventions, but you do have to take steps to tell PHP where your clock lives if you want to avoid a heap of warning messages in your error file. 
