Following is the code to get the login & logout link.
//check the user is loggedon or not if (! Mage::getSingleton('customer/session')->isLoggedIn()){ //if user logged on show the logout link - add this code within anchor tag echo Mage::helper('customer')->getLoginUrl(); } else{ //if user is not logged on yet show the login link - add this code within anchor tag echo Mage::helper('customer')->getLogoutUrl(); }
Here are more variable’s that may you need to get the customer data on the frontend.
bool customerHasAddresses () string getAccountUrl () Mage_Customer_Model_Customer getCurrentCustomer () Mage_Customer_Model_Customer getCustomer () string getCustomerName () string getDashboardUrl () string getEditPostUrl () string getEditUrl () string getEmailConfirmationUrl ([string $email = null]) string getForgotPasswordUrl () Mage_Customer_Model_Entity_Group_Collection getGroups () string getLoginPostUrl () string getLoginUrl () string getLogoutUrl () string getRegisterPostUrl () string getRegisterUrl () bool isConfirmationRequired () bool isLoggedIn () bool isRegistrationAllowed ()
Source : www.adeelishfaq.com/blog/how-to-get-the-login-logout-url-in-magento/