We had covered various ways to update your Twitter status from Google+ using Chrome extensions as well as Agent G. ManageFlitter is a nice service which can automatically post to your Twitter account without the use of any Google Chrome extensions. You just need to authorise the service to use your Twitter account to post the update (similar to any web app for Twitter) and once done, any update in Google+ will be posted to your Twitter account.
Any updates on Google+ which are longer than 140 characters will be linked back to your post on Google+ which is again a good feature. It might take anywhere between 5 minutes to 1 hour for your Google+ updates to get tweeted out via your account.
You must make your posts public on Google+ for them to appear on Twitter. You can also selectively post to Twitter using the advanced options available in the service.
Manage Flitter is a nice service to automatically post to Twitter from Google+.