Devilnet

Copperblade: that’s right – multiple instance just means that you can add it more than once in the sidebar, rather than only being able to use it once. I just updated it so it works using the newer widgets API – pretty much all new widget do the multiple-instance thing by default.
Hope it’s helpful!

This plugin is great, I was recently asked to make it into a multiple-instance widget and adapted it to the new API.
It was worked on by Myself and user Davemac.

I don’t know if you want to do a version update or if you’d like to make a new widget, but the code for multiple-instance is below:

function wpms_recent_posts_mu($how_many=10, $how_long=0, $titleOnly=true, $begin_wrap="\n<li>", $end_wrap="</li>") {
	global $wpdb;
	global $table_prefix;
	$counter = 0;

		// get a list of blogs in order of most recent update. show only public and nonarchived/spam/mature/deleted
	if ($how_long > 0) {
		$blogs = $wpdb->get_col("SELECT blog_id FROM $wpdb->blogs WHERE
			public = '1' AND archived = '0' AND mature = '0' AND spam = '0' AND deleted = '0'
			AND last_updated >= DATE_SUB(CURRENT_DATE(), INTERVAL $how_long DAY)
			ORDER BY last_updated DESC");
	} else {
		$blogs = $wpdb->get_col("SELECT blog_id FROM $wpdb->blogs WHERE
			public = '1' AND archived = '0' AND mature = '0' AND spam = '0' AND deleted = '0'
			ORDER BY last_updated DESC");
	}

	if ($blogs) {
		// Should we make <ul> optional since this is a widget now?
		echo "<ul>";
		foreach ($blogs as $blog) {
			// we need _posts and _options tables for this to work
			$blogOptionsTable = $wpdb->base_prefix.$blog."_options";
		    	$blogPostsTable = $wpdb->base_prefix.$blog."_posts";
			$options = $wpdb->get_results("SELECT option_value FROM
				$blogOptionsTable WHERE option_name IN ('siteurl','blogname')
				ORDER BY option_name DESC");
		        // we fetch the title and ID for the latest post
			if ($how_long > 0) {
				$thispost = $wpdb->get_results("SELECT ID, post_title
					FROM $blogPostsTable WHERE post_status = 'publish'
					AND ID > 1
					AND post_type = 'post'
					AND post_date >= DATE_SUB(CURRENT_DATE(), INTERVAL $how_long DAY)
					ORDER BY id DESC LIMIT 0,1");
			} else {
				$thispost = $wpdb->get_results("SELECT ID, post_title
					FROM $blogPostsTable WHERE post_status = 'publish'
					AND ID > 1
					AND post_type = 'post'
					ORDER BY id DESC LIMIT 0,1");
			}
			// if it is found put it to the output
			if($thispost) {
				// get permalink by ID.  check wp-includes/wpmu-functions.php
				$thispermalink = get_blog_permalink($blog, $thispost[0]->ID);
				if ($titleOnly == false) {
					echo $begin_wrap.'<a href="'
					.$thispermalink.'">'.$thispost[0]->post_title.'</a> <br/> by <a href="'
					.$options[0]->option_value.'">'
					.$options[1]->option_value.'</a>'.$end_wrap;
					$counter++;
					} else {
						echo $begin_wrap.'<a href="'.$thispermalink
						.'">'.$thispost[0]->post_title.'</a>' . $end_wrap;
						$counter++;
					}
			}
			// don't go over the limit
			if($counter >= $how_many) {
				break;
			}
		}
		echo "</ul>";

	}
}

class wpms_recent_posts extends WP_Widget {

	// The widget construct.
	function wpms_recent_posts() {
		$widget_ops = array( 'classname' => 'widget_WPMS_Recent_Posts', 'description' => __( "Display Recent Posts from all WPMS sites Multiwidget" ) );
		$this->WP_Widget('recentPosts', __('WPMS Recent Posts Multiwidget'), $widget_ops);
	} // End function wpms_recent_posts

	// This code displays the widget on the screen.
	function widget($args, $instance) {
		extract($args);

		$options = get_option("wpms_recent_posts_widget");

		if (!is_array( $options )) {
			$options = array(
				'title' => 'Last Posts',
				'number' => '10',
				'days' => '-1'
			);
		}

		echo $before_widget;

		if(!empty($instance['title'])) {
			echo $before_title . $instance['title'] . $after_title;
		}
		wpms_recent_posts_mu($instance['number'],$instance['days'],true,"\n<li>","</li>");
		echo $after_widget;
	} // End function widget.

	// Updates the settings.
	function update($new_instance, $old_instance) {
		return $new_instance;
	} // End function update

	// The admin form.
	function form($instance) {		

		echo '<div id="wpms_RecentPosts-admin-panel">';
		echo '<label for="' . $this->get_field_id("title") .'">WPMS Recent Posts Title:</label>';
		echo '<input type="text" class="widefat" ';
		echo 'name="' . $this->get_field_name("title") . '" ';
		echo 'id="' . $this->get_field_id("title") . '" ';
		if(empty($instance['title'])) {
			echo 'value="Recent Posts" />';
		}
		else {
		echo 'value="' . $instance["title"] . '" />';
		}
		echo '<label for="' . $this->get_field_id("number") .'">Number of posts to show:</label>';
		echo '<input type="text" size="3" ';
		echo 'name="' . $this->get_field_name("number") . '" ';
		echo 'id="' . $this->get_field_id("number") . '" ';
		if(empty($instance['number'])) {
			echo 'value="10" />';
		}
		else {
		echo 'value="' . $instance["number"] . '" />';
		}
		echo '<label for="' . $this->get_field_id("days") .'">Number of days to limit:</label>';
		echo '<input type="text" size="3" ';
		echo 'name="' . $this->get_field_name("days") . '" ';
		echo 'id="' . $this->get_field_id("days") . '" ';
		if(empty($instance['days'])) {
			echo 'value="-1" />';
		}
		else {
		echo 'value="' . $instance["days"] . '" />';
		}

		echo '<input type="hidden" ';
		echo 'name="wpms_recent_posts_submit" ';
		echo 'id="wpms_recent_posts_submit" ';
		echo 'value="1" />';

		echo '</div>';

	$options = get_option('wpms_recent_posts_widget');

	if (!is_array( $options )) {
		$options = array(
			'title' => 'Last Posts',
			'number' => '10',
			'days' => '-1'
		);
	}

	if ($_POST['wpms_recent_posts_submit']) {
		$options['title'] = htmlspecialchars($_POST['wpms_recent_posts_title']);
		$options['number'] = intval($_POST['wpms_recent_posts_number']);
		$options['days'] = intval($_POST['wpms_recent_posts_days']);
		update_option("wpms_recent_posts_widget", $options);
	}

	} // end function form

} // end class wpms_recent_posts

// Register the widget.
add_action('widgets_init', create_function('', 'return register_widget("wpms_recent_posts");'));
?>