PrivatePhone offers a service where you can get a free phone number. It's a real number that you can give out when you need to give out a phone number, but you don't want people to have your "real" phone number. Calls to your PrivatePhone phone number go directly to a voice mail message that you record. You can then optionally get an email or an instant message when new messages are left on your number. You can check your messages from any phone.

If you need to hand out a phone number, but you want to stay anonymous, this is a great service.