Steve asks: "I have an office phone, home phone and cell phone. My friends never know which one to call to find me. Is there a way to simplify my life and give out a single phone number?"
That's a great question and this is the first in a series of tips we will do that all have the same simple free answer.
The answer is to use the free service provided by Google: Google Voice.
If you have a Gooogle account you can simply sign up for Google Voice once you have logged into your Google account. If you don't have one, you can easily create a Google account and then add Google Voice to your account.
Google Voice allows you to select a free local phone number (often in a specific telephone area code and exchange). Given that number, you can set up "real" phone numbers that Google will ring when someone calls your Google Voice number. For example, I have one Google Voice number that I hand out to all my friends and relatives. It calls me at my home, cell, and office numbers. I can control via the web site exactly when it calls me at each of those number, or which it calls first.
You can pick up the call at any of your phones and the caller will have no idea where they reached you. You can easily transfer incoming calls between the phones associated with your Google Voice account, and what's more, Google Voice includes voice mail service that converts the recorded message to text and can email you the transcript of the voice mail message, so you don't need to listen to the message to determine what the caller wanted. (The transcription service isn't perfect, but it's awfully good.)
Google Voice is a wonderful, free service. It's possible that Google might charge for the service at some point, but for now it's free. We use it every day and couldn't possibly recommend it any higher.