So Google+ is live, but for the moment, you’ll need either an existing user to share a post with you, or score your own invite directly. UPDATE: Google has "shut down the invite mechanism for the night" .
Sorry guys! More at: Google+ Invites Halted Due To “Insane Demand”
So What is Google+ Anyway?
It’s a little like Facebook, but also very different. Inside Google+, you can selectively share updates with certain people (kind of like Twitter lists) using the Circles feature. You can also add contacts to multiple Circles. Meanwhile, the Sparks page on Google+ lets you type in topics of interest and discover new content streams.
The Hangouts area is basically group voice and video chat (with text thrown along for ride). You can even watch YouTube videos in sync together. More: [Google+]