Prepopulate field whenever it's used

Thanks for the reply.

I've already had a look at the Prepopulate module, but it doesn't really work well for CCK fields - especially not when they're in groups. Then the reference for the field is something like $form['group']['field_something'][0]['#default_value']['value'] as far as I can remember.

What I really could use is a method that iterates the form object and finds the proper location of the form_something field (independent on what group it is in) and then assigns it some value. This is because I'm using field_something a lot of places and in differently named groups.

Great - thanks to your help I managed to create a working solution with some changes to the Preload module.

Here's the code if anyone else should stumble upon this post in the future:

function altomtrekroner_form_alter(&$form, $form_state, $form_id) {

	if($form['#id'] == 'node-form'){

		
		$field_name_value = '';
		$field_phonenumber_value = '';
		$field_email_value = '';

		//Get cookie values
		$cookievalues = $_COOKIE['contactfields'];
		if(!is_null($cookievalues))
		{
			if(!is_null($cookievalues['name']))
				$field_name_value = $cookievalues['name'];
				
			if(!is_null($cookievalues['phonenumber']))
				$field_phonenumber_value = $cookievalues['phonenumber'];
				
			if(!is_null($cookievalues['email']))
				$field_email_value = $cookievalues['email'];
		}
		//If they don't exist - use user values
		else
		{
			global $user;
			$field_name_value = $user->name;
			$field_phonenumber_value = '';
			$field_email_value = $user->mail;
		}
		
		//Prepare the array with field names and arrays.
		$fields = array(
			'field_name' =>  		array(0 => $field_name_value),
			'field_phonenumber' =>  array(0 => $field_phonenumber_value),
			'field_email' => 		array(0 => $field_email_value)
		);
		
		//Iterate the form array and set
		foreach (array_keys($fields) as $fieldname) {
			if (element_child($fieldname) && !is_null($form[$fieldname])) {
				_altomtrekroner_get_walk($form[$fieldname], $fields[$fieldname]);
			}
		}
  	}
}

function _altomtrekroner_get_walk( & $form, & $fieldsslice) {
  
	if (is_array($fieldsslice)) {
		
		//If we're at the end of the tree
		if (!is_null($form['#default_value'])) {
		
			//The default value should always be an array
			if (!is_array($form['#default_value'])) {
				// Something went wrong so stop here.
				return;
			}
			
			$form['#default_value'] = array_merge($form['#default_value'], $fieldsslice);
		}
		else {
			//Go a step deeper - this is basically the [0]-thingies
			foreach (array_keys($fieldsslice) as $fieldname) {
				if (element_child($fieldname) && is_array($form) && !is_null($form[$fieldname])) {
					_altomtrekroner_get_walk($form[$fieldname], $fieldsslice[$fieldname]);
				}
			}
		}
	}
	else {
		//Field found - now setting default value
		$form['#default_value']['value'] = $fieldsslice;
		if(!is_null($form['#default_value']['email']))
			$form['#default_value']['email'] = $fieldsslice;
	}
}

function altomtrekroner_nodeapi(&$node, $op) {
	if ($op == 'insert') {
		$field_name_value = $node->field_name[0]['value'];
		$field_phonenumber_value = $node->field_phonenumber[0]['value'];
		$field_email_value = $node->field_email[0]['email'];
		
		setcookie("contactfields[name]", $field_name_value);
		setcookie("contactfields[phonenumber]", $field_phonenumber_value);
		setcookie("contactfields[email]", $field_email_value);
	}
}

Basically the module (called altomtrekroner) sets the default values for three fields (currently they're hard coded - but you could easily create a solution that take the field names from a list and does the same thing - I just won't bother today) based on the following conditions

- If the user has saved a node with values for the fields previously, those values are loaded as default the next time.
- If the user has never used those fields before values from the user profile are used (if the user is logged in of course).

The values are stored in a cookie.