BuddyPress.org

How about just sending the message to yourself and checking off “This is a notice to all users.” Otherwise, I’d probably try the Sitewide newsletters plugin, as well. But if you really want to regularly spread and market newsworthy information, I’d def recommend something like MailChimp — http://www.mailchimp.com/features/ — since that has more of a CRM backend with some analtyics to improve on those mass emails.