Untested, but you should be able to get the Page's URL by doing the following:
$jSession =& JFactory::getSession();
$pageInfo = $jSession->get('jfbcCanvasPageInfo', null);
if ($pageInfo)
$pageUrl = $pageInfo['link'];
else
$pageUrl = null;Let us know if that does (or doesn't work). The other information you can get about the page can be found:
developers.facebook.com/docs/reference/api/page/
The Page Info is stored in the session, which means that even if the user navigates away from the Page landing page, you can get what Page they entered on later on during that visit. Once they 'pop out' to your site though (and leave the FB environment), the jfbcCanvasPageInfo variable is cleared, so you'll need to save it if you expect the user to hop back and forth between your site and your site in a FB Page Tab.
Alex
Ability to link a Facebook page to the profile viewed ?
