I found out today I received my official invitation to activate Google Voice. So I now have a new number (which cost me nothing) that I can use to route calls to my iPhone, work phone, or home phone or just to collect VoiceMail messages (and even have them sent to me in transcribed text format as e-mails). And I can customize the response depending on who is calling me.
I now have to figure out my strategy for sharing this new number: who gets it and on what basis.
If you want to more about Google Voice, you read about it and can watch a short video and request an invitation.