As promised, Google+ is now obtainable for Google Apps users. Administrators can allow the new service from the control panel, as explained here. Google+ requires that Picasa Web Albums and Google Talk are enabled and that the organization uses the new accounts infrastructure. If the two services are enabled and the choice to automatically add new services is selected, Google+ is routinely enabled.
After the enabling the service, you require to wait a few minutes until you can use it. Obviously, users have to physically join Google+ by visiting plus.google.com. "Google Apps users will have access to the same set of features that are obtainable to every Google+ user, and more. In addition to sharing publicly or with your circles, you'll also have the alternative to share with everyone in your organization, even if you haven't additional all of those people to a circle," explains Google.
It's interesting that Google+ is obtainable for higher education institutions, but not for other education institutions because users have to be at least 18 years old to use Google+.
You almost certainly noticed that Google+ evolves incredibly fast, faster than any other Google service. The support for Google Apps is not the only new quality: there's Hot on Google+ (a section that highlights popular posts), Ripples (a visualization tool for public shares and comments) and a Creative Kit for photo editing powered by Picnik.