Go to manageflitter.com/plus
Go to your Google+ Profile tab and copy your webaddress. It should look like something like this:
Copy and and paste it into the manageflitter.com/plus , sign into your Twitter account and there you are done! However a few things to note. The update is NOT immediate. It may take up to an hour for the Google+ post to appear in Twitter. Also it is only a one way communication thing. You cant post to Google+ from your Twitter account.