Get a page URL using only the Slug?
Completely untested, but something like this should work:

public function getPageUrl($slug)
{
    $criteria = craft()-&gt;elements-&gt;getCriteria(ElementType::Entry);
    $criteria-&gt;slug = $slug;
    $entry = $criteria-&gt;first();

    if ($entry)
    {
        return UrlHelper::getUrl($entry-&gt;uri);
    }
}