If you would like to move the currency switcher from the left column to the header, you can use the following instructions to do so!
Open /app/design/frontend/default/default/layout/page.xml
Locate:
<block type="page/html_header" name="header" as="header">
Change to:
<block type="page/html_header" name="header" as="header"> <block type="directory/currency" name="currency" template="directory/currency.phtml"/>
Open /app/design/frontend/default/default/template/page/html/header.phtml
After:
<?php echo $this->getChildHtml('store_language') ?>
Insert:
<?php echo $this->getChildHtml('currency') ?>
Save, Upload + Clear Cache
Make sure you have imported or manually entered your Currency Rates otherwise the switcher will not appear!
Its as simple as that!!
Source:http://www.pauldonnelly.net/magento-move-currency-switcher-to-the-header/