WordPress
[php]
<$mt:ArchiveLink with_index="1" setvar="canonical_url"$>
[/xml]
[SOURCE]
TextPattern
[xml]
” />
[/xml]
Executing canonical tags on these next CMS’s varries widely on how each is setup. Therefore, use the following plugins to get it just right.
Drupal & Magento
http://yoast.com/canonical-url-links/
Joomla!
http://extensions.joomla.org/search?q=canonical
ExpressionEngine
http://expressionengine.com/archived_forums/viewthread/107051/