Anyone using this?

I'm not sure I understand how it works

Yes I am

Google + is basically Google's take on social networking ala facebook and twitter etc.
The advantage as they see it is that their network has the performance and reliability to sustain all the content.
In addition, all other google apps and products (ie youtube and picasa) socially compatible.

Its good that it offers circles of friends so you can effectively separate what you discuss with who and who gets too see what... ie.. mates, work, family
Whether it will overtake facebook or twitter is another matter.

Well, given that facebook appears to have gone bonkers again with its new-look homepage, I might be tempted to give this Google+ a bit more of a chance.

how do you get it?

just set up an account at gmail.com / google then search for google plus, couldnt be easier