<?php add_action('admin_menu', 'add_gcf_interface');

function add_gcf_interface() {
	add_options_page('Global Custom Fields', 'Global Custom Fields', '8', 'functions',	
	'editglobalcustomfields');
}

function editglobalcustomfields() { ?> 

	<div class=\"wrap\">
		<h2>Global Custom Fields</h2> 
		<form method=\"post\" action=\"options.php\"> 
		<?php wp_nonce_field('update-options') ?>
			<p><strong>Amazon ID:</strong><br /> 
				<input type=\"text\" name=\"amazonid\" size=\"45\"
				value=\"<?php echo get_option('amazonid'); ?>\" />
			</p> 
			<p><input type=\"submit\" name=\"Submit\" value=\"Update Options\" /></p> 
			<input type=\"hidden\" name=\"action\" value=\"update\" />
			<input type=\"hidden\" name=\"page_options\" value=\"amazonid\" /> 
		</form>
	</div>
	
<?php } ?>