Google recently announced they have added the ability to share circles.
A new “Share” link now appears when you hover over a circle on the Google+ Circles page. Clicking the link will let you add a comment and then share that circle with your friends on Google+.
Two things to note – 1) this only shares the members of the circle are shared, not what you’ve named the circle and 2) only the current members of the circle are shared. If you had new members to a circle, you will have to share the circle again.
Here is a short video from one of the engineers on the Google+ team showing how to share your circles
Bill Brelsford Small Business Marketing Consultant