This is a demonstration plugin that shows how to add a custom link in the footer with Admin Page Framework ( v1.0.4.x ).

admin-page-framework-demo-footer-link.php

<?php
/* 
	Plugin Name: Admin Page Framework - Footer Link Demo
	Plugin URI: http://en.michaeluno.jp/admin-page-framework
	Description: Demonstrates how to add a custom link in the footer.
	Author: Michael Uno
	Author URI: http://michaeluno.jp
	Version: 0.0.2
	Requirements: PHP 5.2.4 or above, WordPress 3.2 or above. Admin Page Framework 1.0.4.x or below.
*/ 

if ( ! defined( 'ABSPATH' ) ) exit;		// Exit if accessed directly

if ( ! class_exists( 'Admin_Page_Framework' ) ) 
	include_once( dirname( __FILE__ ) . '/classes/admin-page-framework.php' );
		
class AdminPageFramework_FooterLink extends Admin_Page_Framework {
	
	public function SetUp() {
		
		$this->SetRootMenu( 'Settings' );	
		$this->AddSubMenu(
			'Admin Page Framework - Footer Link',		// page and menu title
			'apf_footer_link_settings'		// page slug
		);		
		
		$this->AddFormSections( 
			// Section Arrays - numerically indexed.
			array( 	
				// Section Array 
				array(  
					'pageslug' => 'apf_footer_link_settings',
					'id' => 'company_info', 
					'title' => __( 'Company Information', 'apf-footer-link' ),
					'description' => __( 'Information about your company.', 'apf-footer-link' ),
					'fields' => array(	// Field Arrays
						// Text Field
						array(  
							'id' => 'company_url', 
							'type' => 'text',
							'title' => __( 'URL', 'apf-footer-link' ),
							'description' => __( 'The web site of the company', 'apf-footer-link' ),	
							'size' => 80
						),
						array(  
							'id' => 'company_name', 
							'type' => 'text',
							'title' => __( 'Name', 'apf-footer-link' ),
							'description' => __( 'The name of the company.', 'apf-footer-link' ),	
							'size' => 80
						),				
						array(  
							'id' => 'company_description', 
							'type' => 'textarea',
							'title' => __( 'Description', 'apf-footer-link' ),
							'description' => __( 'The description of the company.', 'apf-footer-link' ),
						),			
						array(
							'id' => 'company_sumibt',
							'type' => 'submit',
							'label' => __( 'Save Changes', 'apf-footer-link' ),
						),
					)
				),
			)
		);
		
		if ( isset( $_GET['page'] ) && $_GET['page'] == 'apf_footer_link_settings' )
			add_filter( 'admin_footer_text' , array( $this, 'AddInfoInFooterLeft' ) );	
		
	}
	
	
	public function AddInfoInFooterLeft( $strHTML ) {
		
		$arrOptions = get_option( 'apf_footer_link' );
		return $strHTML 
			. '<p style="float:left; clear: left;">' 
			. '<a href="' . $arrOptions['apf_footer_link_settings']['company_info']['company_url'] . '" target="_blank">'
			. $arrOptions['apf_footer_link_settings']['company_info']['company_name']
			. '</a>'
			. ' - ' . $arrOptions['apf_footer_link_settings']['company_info']['company_description']	// $array[ option key ][ section id ][ field id ]
			. '</p>';
		
	}
	
}

if ( is_admin() )
	new AdminPageFramework_FooterLink( 
		'apf_footer_link',	// the first parameter specifies the option key to use. If not set, each page slug will be used for the key.
		__FILE__			// this tells the framework the caller script path so that the script info will be embedded in the footer.
	);