Op-diverting using Google Voice

I’ll start out by telling you how to do what I’m going to describe, then go into details what it all means.
Replace all instances of xxx-xxx-xxxx with your Google Voice number.

• Dial *67xxx-xxx-xxxx from a phone attached to your Google Voice account
• Enter your PIN, if required
• Dial 2, to place a call
• Dial 800-444-4444
• Ta-da, you’ve sent MCI a spoofed AIN (for me, it reads 404-260-5532)

Ok, so first things first. What is an AIN and why do you care?
AIN stands for Automatic Number Identification. It’s like caller ID (CPN – Calling Party Number) on steroids. You can’t, normally, stop it from being sent, like you can with a CPN. The AIN is not generally available to the person receiving the call (at least not most consumers), like a CPN is.
So if this information isn’t available to Average Joe, why would you want to spoof it? It comes in handy when calling 800 (etc) numbers. Toll-free numbers are not subject to the same caller ID blocking mechanisms (*67) that Average Joe is.
Most PBX systems are able to spoof CPN, but still send the correct AIN.

References:
http://www.docdroppers.org/wiki/index.php?title=ANI_and_Caller_ID_Spoofing