How to Add Links to Top Links in Magento Modern Theme

edit header.phtml

where you see this

getWelcome()?> | getChildHtml('topLinks') ?>

edit it to

getWelcome()?> | getChildHtml('topLinks') ?> | putyour link here

for example

getWelcome()?> | getChildHtml('topLinks') ?> | <a href='about.php'>About Us</a>