Enable skype and callto protocols with Drupal 6

The bad guy is filter_xss_bad_protocol(), which allows for all kinds of protocols, but not skype. Because it uses a (hidden) variable, you can change it by hand using one of the following methods: This works or D5 as well.

1. If you have devel module, execute this code in the "Execute PHP" block:
<?php variable_set('filter_allowed_protocols', array('http', 'https', 'ftp', 'news', 'nntp', 'telnet', 'mailto', 'irc', 'ssh', 'sftp', 'webcal', 'rtsp', 'skype')); ?>
2. Or you can hardcode the value in your settings.php file. Scroll down to the bottom of the settings.php file and you'll find a commented out section of code like this:
 
<?php 
# $conf = array( 
#   'site_name' => 'My Drupal site', 
#   'theme_default' => 'minnelli', 
#   'anonymous' => 'Visitor', 
# );
?>
add this code nearby:
 
<?php
  $conf = array(
    'filter_allowed_protocols' => array('http', 'https', 'ftp', 'news', 'nntp', 'telnet', 'mailto', 'irc', 'ssh', 'sftp', 'webcal', 'rtsp', 'skype')
  );
?>