Several months ago I tried using Skype and it wouldn’t allow you to display your Skype-In number as the caller id to people you were calling. This was frustrating and I even sent a letter to the CEO of Skype about it. However, as Hayden Tompkins pointed out, this now works–I just hadn’t checked it since it was fixed. You may have to manually enable it, but logging into your account and going into the Caller ID preferences. This is a great improvement because many people will just ignore calls that say UNKNOWN or from strange looking numbers.