Easiest way for someone new to Drupal would be to go the Global Theme Settings

( Admin >> Site Building >> Themes >> Settings) - http://your-domain.com/admin/build/themes/settings

Look for the section on the right "Display post information on" and toggle off the type(s) you don't want this to display on

N.B. Not your selected theme's settings!

You could also delete the line that prints your "submitted" info (in your node.tpl.php) or create a specific node template that only did it for a certain node or node type. Although I would imagine the Global Theme Settings will be sufficient.