A simple Wordpress plugin/theme options class. This is basically from the Codex and I just modified it to use class properties to make customizing it a little simpler.

my_wp_settings.class.php

<?php
/**
 * Plugin/Theme Options
 * 
 * @link http://codex.wordpress.org/Creating_Options_Pages#Example_.232
 * @link https://gist.github.com/amereservant/5779754
 * @requires  Wordpress 3.5.1 =<
 */
class wctest
{
    private $_option_name = '_my_plugin_options';
    private $_option_group = 'test_option_group';
    private $_capability = 'manage_options';
    private $_menu_slug  = 'test-setting-admin';
    private $_page_title = 'Settings Admin';
    private $_menu_title = 'Premium Opts';
    private $_section_id = 'setting_section_id';
    
    
    public function __construct()
    {
        if( is_admin() )
        {
          add_action('admin_menu', array($this, 'add_plugin_page'));
	        add_action('admin_init', array($this, 'page_init'));
	    }
    }
	
    public function add_plugin_page()
    {
        // This page will be under "Settings"
	    add_users_page($this->_page_title, $this->_menu_title, $this->_capability,
	        $this->_menu_slug, array($this, 'create_admin_page'));
    }

    public function create_admin_page()
    { ?>
	    <div class="wrap">
	        <?php screen_icon(); ?>
	        <h2><?php echo $this->_page_title; ?></h2>			
	        <form method="post" action="options.php">
	        <?php
                // This prints out all hidden setting fields
		        settings_fields($this->_option_group);	
		        do_settings_sections($this->_menu_slug); ?>
	            <?php submit_button(); ?>
	        </form>
	    </div><?php
    }
	
    public function page_init()
    {		
	    register_setting($this->_option_group, $this->_option_name, array($this, 'validate_settings'));

		// Adds a "group" of settings on the settings page
        add_settings_section(
	        $this->_section_id,
	        'Setting',
	        array($this, 'print_section_info'),
	        $this->_menu_slug
	    );	
		// Adds a field to the "group" created with add_settings_section
	    add_settings_field(
	        'some_id', 
	        'Some ID(Title)', 
	        array($this, 'create_an_id_field'), 
	        $this->_menu_slug,
	        $this->_section_id			
	    );		
    }
	
    public function validate_settings($input)
    {
        if(is_numeric($input['some_id']))
        {
	        $val = $input['some_id'];
	        //if(get_option('test_some_id') === FALSE){
		    //add_option('test_some_id', $val);
	        //}else{
		    //update_option('test_some_id', $val);
	        //}
	    }
	    else
	    {
	        $val = '';
	    }
	    return $input;
    }
	
    public function print_section_info()
    {
	    print 'Enter your numeric value below:';
    }
	
    public function create_an_id_field(){
        $val = $this->get_option('some_id');
        ?><input type="text" id="input_whatever_unique_id_I_want" name="<?php echo $this->_option_name; ?>[some_id]" value="<?php echo $val; ?>" /><?php
    }

    public function get_option( $option, $default=false )
    {
        $opt = get_option($this->_option_name);
        if( isset($opt[$option]) )
            return $opt[$option];
        return $default;
    }
}

$wctest = new wctest();

I intentionally left this stripped down as much as possible for ease of understanding and faster development. It's a basic snippet to get you started on making your own theme/plugin options page(s) in WordPress.