Yes, you can use this code to dynamically show login/ log out:
<?php if(WA_Auth_RulePasses("Logged in to users")){ // Begin Show Region ?>
<a href="users_LogOut.php">Log Out</a>
<?php } // End Show Region ?>
<?php if(!WA_Auth_RulePasses("Logged in to users")){ // Begin Show Region ?>
<a href="users_LogIn.php">Log In</a>
<?php } // End Show Region ?>