Custom Options with *Optional in Title label
In Magento custom options, required fields are indicated by a red asterisk *. But what if the client requests that required fields are indicated by *Required , and unrequired fields are indicated by a *Optional?
Screen print of product options with * only on required fields:

Screen print of product options with *Required on required fields and *Optional on unrequired fields:

Edit the file: app\design\frontend\default\client\template\catalog\product\view\options\type\select.phtml
On line 29 find this code:
<?php if ($_option->getIsRequire()): ?><span> *</span>
and change it to this:
<?php if ($_option->getIsRequire()): ?><span> *Required</span>
Now required select menus will be indicated by an asterisk and the word Required.
To specify the *Optional indicator for unrequired fields, add the following code right after the previous code:
<?php elseif ($_option): ?><span> *Optional</span>
Now unrequired select menus will be indicated by an asterisk and the word Optional.