Per the suggestion of Tim Starling I implemented a way for extensions
to display their credits on Special:Version ( see it live at
http://commons.wikimedia.org/wiki/Special:Version ), to add your
credits to the page just include the following in your extension:
$wgExtensionCredits[$type][] = array(
'name' => 'Example extension',
'author' => 'Foo Barstein',
'url' => 'http://wwww.example.com/Example%20Extension/',
);
Where $type is one of 'specialpage', 'parserhook', or 'other'.
Happy hacking.