I'm finishing up a new addon to send listings to Twitter. the addon administration is used to store your twitter account information and to send tweets (one at a time) manually to twitter.
This addon also includes a cron to send the listings to Twitter in groups of 5. It also includes a hook into the listing system that will send listings to twitter when they are added using the listing editor.
I am working on the documentation this week so it should be ready shortly as a commercial addon.
I may include some stats with the addon before I release it. Not sure how valuable that would be since it would only be a count of all listings in the DB and how many have been sent to Twitter.