Login in to Google plus
Go to circles
Click on Find and Invite
Click on More Actions drop down and choose Select All
Now when all are selected, drag and drop them into new circle
Go on your home page in Google+
In the stream box, which is written as Share what’s new ... set your status
When you write something in there it gives an option of sharing it with the circles you have
It also says that EMail people not using Google+, tick yes there
Now when you click share, the people who are not on Google+ will be notified about it by E-Mail and from that email they can join Google+.
Enjoy. If you need an invitation for Google Plus ... leave your email address in the comment!