create a simple wordpress (2.7+) settings page that includes user options. ( option_two can be different for each user ). The uninstall.php file helps remove all the plugin options.

my-plugin.php

<?php

// ...

// create custom plugin settings menu

add_action('admin_menu', 'my_plugin_create_menu');

function my_plugin_create_menu() {

	//create new top-level menu
	add_menu_page('My Plugin Settings', 'My Plugin Settings', 'administrator', __FILE__, 'my_plugin_settings_page', plugins_url('/images/icon.png', __FILE__));

	//call register settings function
	add_action( 'admin_init', 'register_mysettings' );
	
}

function register_mysettings() {
	//register our settings
	register_setting( 'my-plugin-settings-group', 'option_one' );
	register_setting( 'my-plugin-settings-group', 'option_two', 'option_two_cb' );
}

function option_two_cb( $input ) {
	// store the input for the current user and then grab the same variable
	// with get option and replace the input.
	$user = wp_get_current_user();
	update_user_option($user->id, 'option_two', $input);
	$input = get_option('option_two');
	return $input;
}

function my_plugin_settings_page() {
?>
<div class="wrap">
<h2>My Plugin</h2>
	<form method="post" action="options.php">
		<?php settings_options( 'my-plugin-settings-group' ); ?>
		
		<table class="form-table">
			<tr valign="top">
				<th scope="row">Option One:</th>
				<td><input type="text" name="option_one" value="<?php echo get_option('option_one'); ?>" /></td>
			</tr>
			<tr valign="top">
				<th scope="row">Option Two:</th>
				<td><input type="text" name="option_two" value="<?php echo get_user_option('option_two'); ?>" /></td>
			</tr>
		</table>
		
		<p class="submit">
			<input type="submit" class="button-primary" value="<?php _e('Save Changes') ?>" />
		</p>
		
	</form>
</div>
<?php
}

// ...

?>

uninstall.php

<?php

// ...

//delete all options
function my_plugin_uninstall_options() {
	global $wpdb;
	
	$users = $wpdb->get_col( 'SELECT `'. $wpdb->users.ID .'` FROM `'. $wpdb->users .'`' );
	foreach ( $users as $user_id )
		delete_user_option( $user_id, 'option_two' );
	
	delete_option( 'option_one' );
	delete_option( 'option_two' ); // it is used as a fallback
}

my_plugin_uninstall_options();

// ...

?>