WP Slack Notifier Plugin
This is a plugin which sends post published notifications to slack.com webhooks.
If you don't know what the above sentence means, this plugin is not for you. :)
It will send notification messages for posts being published from draft, pending review, or scheduled status. If the post transitions from scheduled to live, the notification will include the word "Scheduled" to indicate this.
Destination channels, source usernames, and icon emoji can be set on a per-post-type basis. Anything left blank will use the defaults from your slack.com settings, with the exception of the recipients field. This is to prevent spam from post types you're not interested in hearing about.
Requires your version of PHP to support curl. Which it ought to.