i want to check via php if a page is a cms_page in Magento. I need diffrent breadcrumbs for cms pages, so im trying to this with a condition, but i have no idea how to or where
The following should give you what you want
//from a block or phtml script
$this->getRequest()->getModuleName()
When this returns the string 'cms', you're on a CMS page.
When Magento's frontend and admin routers can't find a match on your URL, the CMS router takes over. If the CMS router finds a match (based on the CMS pages you've setup), it hands off the request to the cms module and Mage_Cms_IndexController controller.