GrandCentral.com

Most of us have at least three phone numbers—home, work, cell—and don't always know which one to give out, or later regret the choice we made. Grand Central is a free, one-number-ringing-multiple-phones routing service that solves all these problems, while giving you a level of control over your calls that earlier services like it did not. To get started, Grand Central assigns you a number (you can ask for a particular area code, then choose from a list) and you set up the forwarding rules. One obvious advantage is that when you're at your desk, you don't have to waste wireless minutes by taking calls on your cell phone; when you're away from your desk, you don't have to miss business calls ringing in at the office, because all your calls ring at all your phones, all the time. You can white-list your friends and colleagues so their calls come right through. You can also black-list numbers by sending them to the Spam folder or set up the outgoing message ("this phone is not in service") to play for unwanted callers. You can screen calls by listening in as callers are leaving a voicemail message, and then cut in to take the call... or not. You can also record your own calls—pretty handy when you're in the car or on the golf course. Another cool feature is the Call Switch: while you're talking on one phone, you can transfer the call to another without hanging up, or even interrupting the conversation. Note: Basic service is free, but Click-to-Call, Call Record and other features are not. Check out the mobile version at grandcentral.com/mobile.