How do I determine how far I am from my CO?

Your ISP or telephone company should be able to calculate this information for you in airline and/or wire feet. The closer you are to your CO, the higher the speeds you can achieve using DSL.

What is the setup process?

Your telephone company or ISP should be able to run engineering tests on your lines which will determine what speeds are available to you. Decide on a cost/speed package. Get a due date from your ISP (usually within 3 to 30 days). Before the due date, the line up to the Minimum Point of Entry (MPOE) at your home or business will be provisioned for DSL. The hardware will either be available to you for pick up at a local store, or sent to you by the due date. On the due date, technicians will come to your home or business to 'turn up' the circuit, or you will be contacted by phone if you opted for the self-install option. Before this day you should square away the details of your account with your ISP with regard to a regular dial-up account, DNS, IP addresses, and billing.

Can I use my existing regular phone line for DSL or do I need a new line?

In most cases you can use your existing phone line for DSL service. In this case the POTS phone number and billing would remain the same, and any existing special services on the line would also remain unchanged (like call-waiting, message center, etc.). Simultaneous use of POTS service does not "eat into" DSL bandwidth. In some cases a new line has to be installed because of load coils or other DSL-unfriendly devices.