Well I just got my invitation for the Grand Central Beta
Seems pretty cool so far.
The only problem I see, is google owns my number.
Would I really want to distribute it, if it can be taken away?
For a small business with a website, the call me button is nice.
Your customer can click the button, and call all of the phones you have setup.
For that customer that keeps having issues, you can set them up with a peaceful ring, or just send him directly to voicemail.
It will nice to see some integration with google talk. When someone calls you from google talk, it can go to your grand central account. If you are not online, it can ring your phone.
Seems like a nice way to blur the distinction between internet voice communication and traditional voice communication.