Google Voice is amazing. We’ve been using it for about 2 years now and not sure how to live without it. You get one number to give out. That number will ring any of your predefined other numbers.
Example 1: Let’s say you’re a real estate company. At night you could call forward your main number to your Google Voice number. It would then ring ALL your agents until the first one picked up.
Example 2: Let’s say your organization has an “on call” doctor for emergencies. Instead, use a Google Voice number that rings all doctors at once.
Of course you could simply use for personal use – your number rings your cell, work, house, etc.
Google Voice has been in a closed beta for years now (previously Grand Central). Recently Google opened the doors to allow anyone to join. However, you have to sign up for an invitation. It then takes a few weeks or months to get OK’d by Google. Best part? Google Voice is free!