you are wondering if you have to have a BT telephone line to get
broadband then the answer is yes. This may change in the future
and is only in the very early stages of development to allow BT
to be bypassed.
you have cable available in your area then you may be able to get
your internet through this with a cable modem. They offer similar
speeds to broadband ADSL but you would have to check with your local
cable supplier if this is available to you.
such as Virgin
Media offer an option to get broadband
& telephone deals through them.