Passing URL as variable

I have the following link in my code: clickrate.php?site=sitename&link=http://www.clientsite.com/store.php?id=430&action=menu There are two variables I am trying to pass to clickrate, site and link. The full link is http://www.clientsite.com/store.php?id=430&action=menu. The problem is that since the link itself has variables being passed, action is being passed as a separate variable and the full link is getting cut off. I tried using htmlspecialchars, and surrounding the link with quotes, but nothing worked. Any ideas? Thanks, -Lisi