All template variables that display a date can accept a custom date format as a parameter. For example, if you have {LINKDATE} in a template but want to show it in a DD-MM-YY format you can use {LINKDATE[%d-%m-%y]}

The format is the strftime() format ( http://www.php.net/strftime ), the same as you use to specify the default date formats at Admin Panel -> Settings -> Localization.