Question about l() function

Hi,Aaron
Would you like to tell me more about :"http://www.pixelclever.com/how-and-why-use-l-function-create-links-drupal-programming"?

as that:

which file should I put the following code into? :

l($text, $path, $options = array())
or the example: print l('This is the link text', 'node/2');

$options = array(
'attributes' => array(),
'html' => TRUE,
);
l('', 'node/1', $options);

should I type the code in the page.tpl.php or the others?