Adding a logout link to OptionCart is pretty easy to do.
1. create logout.php in shopadmin directory with the following code:
<?php
// logout of shopadmin
// delete our cookie
setcookie("adminpswd", "", time()-42000, '/');
// goto login page
header ("location:index.php");
?>
2. in footer.htm (in shopadmin) I modified it like so (note I changed the copyright symbol to ©)
<p align="center" class="smalltext"> <a href="logout.php">Logout</a><br> OptionCart Deluxe Catalog Version 2.1<br> Copyright © <a href="http://www.optioncart.com">OptionCart.com</a>. All rights reserved.</p>
3. That is it! To logout click on Logout at the bottom of the admin page. It will take you back to the admin login page.