Create a WordPress Recent-Posts Widget

<?php
/*
Plugin Name: My Recent Posts widget
Description: Adds a sidebar widget to display posts from a specified category
Author: Mike Jolley, jolley_small@tesco.net
Version: 1.0
Author URI: http://blue-anvil.com
*/

function widget_myRecentPosts_init() {
 
	if ( !function_exists('register_sidebar_widget') )
		return;

function widget_myRecentPosts($args) {
 
		// "$args is an array of strings that help widgets to conform to
		// the active theme: before_widget, before_title, after_widget,
		// and after_title are the array keys." - These are set up by the theme
		extract($args);
 
		// These are our own options
		$options = get_option('widget_myRecentPosts');
		$title = $options['title'];  // Title in sidebar for widget
		$show = $options['show'];  // # of Posts we are showing
		$excerpt = $options['ex'];  // Showing the excerpt or not
		$exclude = $options['exclude'];  // Categories to exclude
                      if ($show<1) $show = 1;
		if ($exclude=="") $exclude = "0";

                      // Output
		echo $before_widget . $before_title . $title . $after_title;

// GET POSTS
			global $wpdb;
			$sql = 'select DISTINCT * from '.$wpdb->posts.'
			INNER JOIN (select * from '.$wpdb->post2cat.'
			INNER JOIN '.$wpdb->categories .' ON '.$wpdb->post2cat.'.category_id = '.$wpdb->categories .'.cat_ID)
			as A ON '.$wpdb->posts.'.ID = A.post_ID
			WHERE (A.cat_ID NOT IN ('.$exclude.'))
			AND '.$wpdb->posts.'.post_status="publish"
			AND '.$wpdb->posts.'.post_type="post"
                        GROUP BY ID
			ORDER BY '.$wpdb->posts.'.post_date
			DESC LIMIT 0,'.$show.';';
 
			$posts = $wpdb->get_results($sql);

			// start list
			echo '<ul>';
				// were there any posts found?
				if (!empty($posts)) {
					// posts were found, loop through them
					 foreach ($posts as $post) {
 
							// format a date for the posts
							$post->post_date = date("F j, Y",strtotime($post->post_date));
 
							// if we want to display an excerpt, get it/generate it if no excerpt found
							if ($ex) {
								 if (empty($post->post_excerpt)) {
									 $post->post_excerpt = explode(" ",strrev(substr(strip_tags($post->post_content), 0, 100)),2);
									 $post->post_excerpt = strrev($post->post_excerpt[1]);
									 $post->post_excerpt.= " [...]";
								 }
							}
 
							//output to screen
							echo '<li>
							<a class="post" rel="bookmark" href="'.get_permalink($post->ID).'"><span class="inner">
							<strong class="title lifestyle">'.$post->post_date.' - '.$post->post_title.'</strong>';
 
							if ($ex) echo '<br />'.strip_tags($post->post_excerpt);
 
							echo '</span></a></li>';
					 }
				} else echo "<li>No recent Posts</li>";
		// end list
		echo '</ul>';

// echo widget closing tag
		echo $after_widget;
	}

	// Settings form
	function widget_myRecentPosts_control() {
 
		// Get options
		$options = get_option('widget_myRecentPosts');
		// options exist? if not set defaults
		if ( !is_array($options) )
			$options = array('title'=>'Recent Posts', 'show'=>'5', 'excerpt'=>'1','exclude'=>'');

                      // form posted?
		if ( $_POST['recentArticles-submit'] ) {
 
			// Remember to sanitize and format use input appropriately.
			$options['title'] = strip_tags(stripslashes($_POST['recentArticles-title']));
			$options['show'] = strip_tags(stripslashes($_POST['recentArticles-show']));
			$options['excerpt'] = strip_tags(stripslashes($_POST['recentArticles-excerpt']));
			$options['exclude'] = strip_tags(stripslashes($_POST['recentArticles-exclude']));
			update_option('widget_myRecentPosts', $options);
		}

		// Get options for form fields to show
		$title = htmlspecialchars($options['title'], ENT_QUOTES);
		$show = htmlspecialchars($options['show'], ENT_QUOTES);
		$excerpt = htmlspecialchars($options['excerpt'], ENT_QUOTES);
		$exclude = htmlspecialchars($options['exclude'], ENT_QUOTES);

		// The form fields
		echo '<p style="text-align:right;">
				<label for="myRecentPosts-title">' . __('Title:') . '
				<input style="width: 200px;" id="myRecentPosts-title" name="myRecentPosts-title" type="text" value="'.$title.'" />
				</label></p>';
		echo '<p style="text-align:right;">
				<label for="myRecentPosts-show">' . __('Show:') . '
				<input style="width: 200px;" id="myRecentPosts-show" name="myRecentPosts-show" type="text" value="'.$show.'" />
				</label></p>';
		echo '<p style="text-align:right;">
				<label for="myRecentPosts-excerpt">' . __('Show excerpt:') . '
				<input style="width: 200px;" id="myRecentPosts-excerpt" name="myRecentPosts-excerpt" type="text" value="'.$excerpt.'" />
				</label></p>';
		echo '<p>Enter the categories to exclude below, this must be a comma separated list of category id\'s!</p>';
		echo '<p style="text-align:right;">
				<label for="myRecentPosts-exclude">' . __('Exclude:') . '
				<input style="width: 200px;" id="myRecentPosts-exclude" name="myRecentPosts-exclude" type="text" value="'.$exclude.'" />
				</label></p>';
		echo '<input type="hidden" id="myRecentPosts-submit" name="myRecentPosts-submit" value="1" />';
	}

	// Register widget for use
	register_sidebar_widget(array('My Recent Posts', 'widgets'), 'widget_myRecentPosts');
 
	// Register settings for use, 300x100 pixel form
	register_widget_control(array('My Recent Posts', 'widgets'), 'widget_myRecentPosts_control', 300, 200);
}
 
// Run code and init
add_action('widgets_init', 'widget_myRecentPosts_init');
 
?>