Not working

I had some trouble making it work at first as well. My issues were not on the Drupal side, but instead on the SugarCRM side. The default lead capture page (leadCapture.php) expects that the users array contain the username and password for logging into sugar, see lines 49-54 in community edition, version 5.0.0c:

/**
 * To make your changes upgrade safe create a file called leadCapture_override.php and place the changes there
 */
$users = array(
	'PUT A RANDOM KEY FROM THE WEBSITE HERE' => array('name'=>'PUT THE USER_NAME HERE', 'pass'=>'PUT THE USER_HASH FOR THE RESPECTIVE USER HERE'),
);

You need to edit this array with an entry for the user you configure on the sugarform admin page -- the key is what you specify for the username on the Drupal side, and then you add a SugarCRM username and the MD5 hash of the password.

The recommended way to do this on the SugarCRM side is to reassign the value in a file named leadCapture_override.php so that you area upgrade safe (see the comment above).