Google had planned to implement their business version of Google+ in a few months. They had asked companies to wait on that phase before they created business profiles.
If you read the post you have until today July 15 to register your business, although it seems that the form has been turned off as of this post.
If you need more information regarding Google Plus for Business use, feel free to take a look at Christian’s other post where he explained Google’s stance on business users until the next phase.
If you are not in the selected bunch of users who will test phase, I recommend you to build the business on the personal side by creating relationships and really caring about those people you interact with online. Communicating as an individual can lead to healthy business opportunities for the company you own or represent. It can also extend the relationship into a positive perception of the brands you represent.
A good example was Morgan Johnston from Jetblue using it to convey a special deal from his personal account.
Not only will people identify with you as a person, but they will also identify with your company because they know you as a person not as a logo.
I see many benefits of Google + so it is key for any smart business to stay up to date and once it is available, I highly recommend you to sign your business up.