I recently switched to an answering service and I don't think I could ever go back!
It's great at first to be getting calls at first but keep in mind these calls come at all times of day! It's extremely inconvenient to be getting calls while driving, on appointments or just doing something else.
Now My blackberry will receive an email with a transcript of the phone call and all the details I need. DONE!
It's nice to have all the details you need and know which direction your headed with them before you even talk. Also allows you to keep track of your leads a little easier. This service makes it easier for me to just focus on getting as many "emails" as possible.
Get a PO and don't worry about people upset about getting DM. It doesn't happen often and when it does just give them a second to rant and listen. They'll scream for a while and then hang up on you. Who cares? You don't suppose they call Dominoes mad as hell about this pizza special flyer they got today, do you? You didn't do anything wrong. These people are 1. mad at someone else, 2. crazy as hell, or 3. both.
For a phone number I use Google Voice for my "cell phone" number. It's not registered, no one can find you, you can transfer it to ring on any phone and best yet you can turn it off!
PO Box, Live Answering Service, Call them on your google number
Be a professional.