If it is a form, use the GET method and it will automatically send variables to the "action" page.
If not a form, you can send them manually (this may not be the best way at all, but it works):
<?
echo "<a href=\"AssignmentAdd.php3?SSN=$Social_Num&User_LN=$LastName\">"; ?>View</a>"
You can also use session variables, depending on what you are trying to do.