Find Your Google+ User Number
The first thing you will need to do is find your Google+ user number. In order to do this, simply visit your Google+ profile page and look for it in the URL. I have highlighted the number of my user profile below. Be sure to copy (ctrl+c) your number to your clipboard.
Google+ Does Not Have RSS Feeds (Yet)
In order to automate a tweet, you typically need a RSS or XML feed to enter into your choice application or script to post to Twitter (Twitterfeed, Hootsuite, etc). Currently, I am unaware of a RSS or XML link for Google+ accounts (If there are, please let me know where to find them). No worries, as I was able to find an app that will create a RSS feed from a Google+ account on AppSpot.
The app you will need to use is called “PlusFeed” and can be found at http://plusfeed.appspot.com. Using this app will allow us to easily make our own Google+ RSS feed.
Once you are at the PlusFeed page, you will need to paste your Google+ user number to the end of the URL. For example, in your address bar, simply add the following (replace number with your Google+ user number):
Be sure to add the forward slash if it is not already there, resulting in a URL that looks like http://plusfeed.appspot.com/118151624337950943427. This is what we will use for your Google+ RSS feed link.
Add The RSS Link To Your Automation Tool of Choice
Finally, login into your favorite Twitter automation tool and input your Google+ RSS feed link we created in the step above. Adjust your automated tweeting frequency as needed to post more or less frequently as you see fit. Simply save your settings and feed and during the next run of your automation tool, you will see your Google+ posts appear in Twitter as tweets.
Google+ RSS Tip
One thing I noticed when creating the RSS feed is that it will only pull Google+ posts that are visible to everyone. Therefore, if you are only sharing with certain circles, those posts will will not appear in your RSS feed.
While I have not used this extensively, let me know if you run into any issues or figure a better way to do it.