Move mini-cart in the sidebar to the header (or anywhere) in Magento

[This post is from http://www.exploremagento.com/magento/move-cart-to-header-or-anywhere-in-magento.php and really helpfull]

This is not the only way to do this, but it is a useful one.

1) Copy the the block for the cart side bar:

//design/frontend/default/default/layout/checkout.xml
<block type="checkout/cart_sidebar" name="cart_sidebar" template="checkout/cart/sidebar.phtml"/>

//there is also this full code in my version 1.1.3
<block type="checkout/cart_sidebar" name="cart_sidebar" template="checkout/cart/sidebar.phtml" before="-">
<action method="addItemRender"><type>simple</type><block>checkout/cart_item_renderer</block><template>checkout/cart/sidebar/default.phtml</template></action>
<action method="addItemRender"><type>grouped</type><block>checkout/cart_item_renderer_grouped</block><template>checkout/cart/sidebar/default.phtml</template></action>
<action method="addItemRender"><type>configurable</type><block>checkout/cart_item_renderer_configurable</block><template>checkout/cart/sidebar/default.phtml</template></action>
</block>

2) Open up app\design\frontend\default\default\layout\page.xml (assuming you are using the default design or didn’t create a new page.xml file in your own templates)
Find the code :

<block type="page/html_header" name="header" as="header"> //near line 58

Within that block, you will see other sub-blocks.
Paste your new block in there. Add the “as” attribute and set it to “topcart” — final result:

<block type="page/html_header" name="header" as="header">
<block type="page/template_links" name="top.links" as="topLinks"/>
<block type="page/switch" name="store_language" as="store_language" template="page/switch/languages.phtml"/>
<block type="core/text_list" name="top.menu" as="topMenu"/>
<!--new block -->
<block type="checkout/cart_sidebar" name="cart_sidebar" as="topcart" template="checkout/cart/sidebar.phtml"/>
</block>

3) Finally, go into app\design\frontend\default\default\template\page\html\header.phtml (again, assuming your using default theme) and add the code:

//place this where ever you want the cart to show up.
<?php echo $this->getChildHtml('topcart'); ?>

Quick update:
Removing the cart in a CMS page would also be handy to know:
In the Update Layout XML area, use:
You might have to wrap this in

<reference name=”right”> 

(name changing dependent on your design)

<action method="unsetChild"><name>cart_sidebar</name></action>

That’s it!