Incluir scripts y css con add_action

Para agregar los scripts a tu tema de la forma WordPress tienes que modificar el
functions.php
y agregar unas acciones.

function enqueue_js_scripts()
{

// Register the script like this for a theme:
wp_register_script( 'bootstrap-min', get_template_directory_uri() . '/js/bootstrap.min.js', array( 'jquery' ) );
// For either a plugin or a theme, you can then enqueue the script:
wp_enqueue_script( 'bootstrap-min' );
}
add_action( 'wp_enqueue_scripts', 'enqueue_js_scripts' );

function enqueue_css_styles()
{
wp_register_style('css-bootstrap-min', get_template_directory_uri() . '/css/bootstrap.min.css',false,'13.02.05','all');
wp_register_style('css-bootstrap-responsive', get_template_directory_uri() . '/css/bootstrap-responsive.min.css','css-bootstrap-min','13.02.05','all');
wp_register_style('css-main', get_template_directory_uri() . '/css/main.css','css-main','13.02.05','all');
wp_register_style('font-awesome', get_template_directory_uri() . '/css/font-awesome.css','font-awesome','13.02.05','all');
// For either a plugin or a theme, you can then enqueue the style:
wp_enqueue_style( 'css-bootstrap-min' );
wp_enqueue_style( 'css-bootstrap-responsive' );
wp_enqueue_style( 'font-awesome' );
wp_enqueue_style( 'css-main' );
}
add_action( 'wp_enqueue_scripts', 'enqueue_css_styles' ); 

referencias: http://codex.wordpress.org/Function_Reference/wp_enqueue_script