They will find the closest ISP's etc and can find out how far you are from the CO.
But keep in mind the measurement is not always correct. if your telephone provider has any RT's (Remote Terminal's) You may be alot closer then what is reported. It is best to first see the estimate, then call the company you are interested in.
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS