If you are using thematic child theme go to thematic-functions.php file in your child theme and add this:
// Add a Home link to your menu
function childtheme_menu_args($args) {
$args = array(
'show_home' => 'Home', //here change Home to whatever you like
'sort_column' => 'menu_order',
'menu_class' => 'menu',
'echo' => true
);
return $args;
}
add_filter('wp_page_menu_args','childtheme_menu_args');
If you have this function just change it… But if you need to convert the file to utf8 (if the link should be renamed in Cyrillic for example) it’s better to use the second way down because otherise you are going to see strange symbols when you are reloading your wordpress pages
Additionaly you could open your functions.php file and add this:
function change_home($menu_text) {
return preg_replace('/>Home</', '>Blog<', $menu_text, 1);
}
add_filter('wp_page_menu','change_home');
Also this links could be usefull:
http://wordpress.org/support/topic/wp_page_menu-re-name-home