The admin_items_form_tabs filter allows you to add, remove, or modify the tabs on the edit item form.
class MyPlugin extends :php:class:`Omeka_Plugin_AbstractPlugin`
{
protected $_filters = array('admin_items_form_tabs');
public filterAdminItemsFormTabs($tabs, $args)
{
$item = $args['item'];
$tabs["My Plugin"] = uri('/my-plugin/edit/id/' . $item->id);
}
}